Thread: How do engines die?

So, my current car is the first one I had this long and that's been aging in my possession. I'm planning on keeping it forever (or whatever practical with cars that may mean) and did replace the transmission two years ago and little by little took very good care of it at lower and lower costs while little by little becoming an expert about everything about it.

It currently has close to 150K miles. It has an indicator of "oil age" or "oil life time" that decreases with time and is manually reset back to 100% at the time of oil changes. I've always been using this number in addition to miles and time to make the oil change decisions.
I usually change engine oil with the best high-mileage brands every time that age gets to around 55% which most of the time makes me change oil every month (too frequent, I guess!). In the last 10-20K miles, I started loosing some oil between changes (aging, tear and wear) that may get up to 1qt loss. I have the following questions:

1.If, theoretically, I change oil every 2 months, and add a qt every week (hypothetically), doesn't that make for more than a total oil change (disregarding the filter)?

2. If the answer to 1 is "yes" or "kinda", then can I start increasing the time/miles between oil changes? (probably from 55% to, say, 25% of oil age)

3. Is there an upper limit for the amount of lost/burned engine oil at which some kind of diagnosis/inspection/repair has to be done? and what usually, is the repair?

4. If the answer to 3 is no, and that engines can get to a point where there won't be any need for oil changes because oil is being ADDED continuously (only filters may be changed from time to time), then when is it a "good" time to rebuild/replace an engine?

5. I heard that replacing is better than rebuilding, and that remanufactured are the best option when it comes to the cost/quality compromise , and I tend to agree with both to some extent. How long (in KMiles) do those 3800 GM engines usually last (original and re-man'ed) for a well taken care of car?

thanks
(my car is a 2008 grand prix with all the luxury options that were available that year, and has close to 150K miles)

I don't pay any attention to the oil life monitor, I just change my oil every 4K miles using regular old oil and a Wix filter. GM says using a quart of oil between changes is normal consumption, which on my motor seems about right. As long as all the gaskets are good you should not be loosing oil anywhere else. Common leak points are the valve cover gaskets and pan gasket, then the rear cover gasket which is hidden by the transmission.

If for some reason you have to replace the entire motor, then I'd just get a low mileage used engine, regasket everything while it's out and throw it in. CORRECTLY rebuilding a 3800 takes a lot of $$ from a machine shop and even then there's no guarantee. Never tried a re-man engine for this car so don't know. I just went used and never looked back. The motor in my 00GT has 302K mi. on it and runs just fine.

cheatah, thank's sir
Answers 4 and 5, and even 3, made me do the "ahaaaaa"

Originally Posted by FordMan77

I don't pay any attention to the oil life monitor, I just change my oil every 4K miles using regular old oil and a Wix filter. GM says using a quart of oil between changes is normal consumption, which on my motor seems about right. As long as all the gaskets are good you should not be loosing oil anywhere else. Common leak points are the valve cover gaskets and pan gasket, then the rear cover gasket which is hidden by the transmission.

If for some reason you have to replace the entire motor, then I'd just get a low mileage used engine, regasket everything while it's out and throw it in. CORRECTLY rebuilding a 3800 takes a lot of $$ from a machine shop and even then there's no guarantee. Never tried a re-man engine for this car so don't know. I just went used and never looked back. The motor in my 00GT has 302K mi. on it and runs just fine.

very cool info there.
I guess, what you referred to as "do the work outside and throw it in", is equivalent to re-man'ed one. I'm only speculating for the far future, then. For the latter I found a price of about $2500, can you please throw a number about what it costs now to do what you did (old-low-miles, replace gaskets, install)?

Also, if you're not visibly loosing oil from a leak (check the front and rear manifolds for sings of oil dripping, which would be a valve cover gasket), then don't forget to change the PCV valve. Could be gunked up causing excess pressure in the crankcase.

When I replaced the engine in mine, I got a motor with around 140K on it for $300. Add in gaskets, coolant and small parts I was right around $500. It pays to shop around places like RockAuto, Ebay, Amazon, etc. I swapped the motor in my garage with no lift and basic hand tools (with some air ones thrown in for speed). Just removed the hood and pulled it out the top.

Ok so lets get some basic ideas out in the world again. and some basic info on oil.
Conventional oil, non blend WAS oil that was cracked from crude oil THEN each manufacturers additive package.
About 10+ yrs ago the EPA started pushing for lower phosphorus and zinc levels (high pressure antiwear additives) so the manufacturers had to add come up with ways to beef up the high pressure capabilities.
THUS they came up with synthetic replacements.
Synthetic means the molecules are engineered in a lab rather that using raw element based like phosphorus and zinc. Synthetic oils are produced the same way, engineered rather than "cracked" from crude to base oils.
Thus when engineering the molecules they are all identical and the characteristics are designed in.
Synthetics have engineered to take the heat and stress and synthetic additive package for foaming, dispersants, detergents etc.
The bad thing is the replacements for zinc(zinc dithiophosphate or ZDDP) and phosphorus cant really be replaced as easy. Blended oils dont actually work as well thus making Brad Penn and Comp Cams high zinc oils useful for older car owners.
Roller cam engines have LESS issue but pitting and wear can still result.
Supposedly the EPA tried "these additives contaminate converters thus they need reduced/removed" then converter makers and OEMs got riled up on that, so they went to "its better for the environment sue to personal oil changes and improper disposal" which well over 90% of old oil IS recycled and very little is "dumped" anymore. I am sure every town had an old rock road just outside of town the county "oiled" so they dump their oil their too. Road oil is a lot different.
Anyway as the oil detergent/dispersant/anti-wear package was perfected, namely to deal with heat and wear and tear, gas reformulation to unleaded, etc the manufacturers and oil companies hit a "happy spot" and advertised 3 month/3000 miles and it worked as the average mileage WAS that.
Now everyone talks about better machine processes, better materials, yada, yada,yada.
Most of the wear on older cars came from carbon buildup, gasoline dilution from carburation, and some from parts getting better. But saying a straight machined cylinder in the 60s is straighter than the 2000s, sorry thats BS.
Now have they gotten better at using less material and DESIGNING stronger castings, sure but now we dont get decent engines that we can bore out a bunch to make bigger. Now we get engines that can only be over bored 10 or 20 thousandths.
When I started doing maintenance plans for businesses and car owners. I always look at severe service intervals rather than "normal" chart as no one is normal.
For granny who parks car and drives every other week to go to store and such, 3month/3000mi is bit overkill as they rarely HIT the 3000mil mark.
But at least every 6 month works.
But some of these car makers are claiming 7500-10000 mi intervals and some people just dont drive that much, but many drive a lot more. I was offered job with old employer but job is like 100mi one way. 5 days a week.
That would be 1000mi a week.
Oil lights work off time, heat,mileage,load algorithm.
Chose an oil/brand/weight that is accepted and stick with it.
Change oil and check in same spot at least weekly and not it with miles. Oil consumption will be two ways, continuously ie burning oil, generally shown with fouling plugs, smoking, etc.
OR from age/wear/tear/breakdown. and will usually happen all in a very short time. This is from oil reaching a limit of dilution/contamination/breakdown.
Many engines have this point and it should be a factor when deciding on oil change intervals.
BUT run an oil change, note when it gets low. I do know you can drive a qt low but you need to note oil level daily if you dont add that first qt. ALSO if you do add that 1st lost qt not how long it takes till it gets low again.
Proper inspection and evaluation depends on observed inspection. Oil level USED to stay high as fuel diluted it THEN when it got high enough the engine would stat consuming the diluted fuel, and as the level gets lower the oil temps go up and fuel boils off.
MOST oil consumption in current engines starts happening after 250-500 miles after new oil gets mixed with left over old oil, and additive package stabilizes in the sump contents.
Keeping proper records help deduce WHAT is going on. A steady diet of oil means mechanical or lubricant issues like worn parts or oil brand/type/weight not suited to your specific use.
You can use different weights, brands, etc.
Blended oil to synthetics, vice versa, or going to next heavy weight, truck oils, what ever.
Keep records and change one thing at a time. Had a customer who wanted Castrol in his car so he brought it. The car started using oil at about 60k, so I offered to change him up and see what happened, had him come by shop every week for oil checks. Switched him to Shell Rotella T, and first oil change at about 2000 miles the filter was HEAVY, the oil was filthy. 3rd oil change car stopped using as much oil.
Now for the other part, we did a tune up at same time, and I did compression test on couple cylinders. So when it quit using oil, the compression actually came up by 15 lbs.
Turns out the owners driving style didnt work using Castrol. So at the shop I worked at we had "Quaker State" which since I found out back then that Shell oil company owns/makes QS and Pennzoil and we started using shops 10w30 and he hasnt had issue since as he kept using same oil even when that shop shut down.
Oils like fuels, tires, even cars need finessing by trial ans error. First figure out if its using, leaking or normal consumption.
Devising a plan to WATCH, and record symptoms may take a bit but going from there is the way to properly decide if the engine is broken, damaged and running or ready to fail.
Crudding up the plugs is generally rings or valve stem seals. BUT on the newer cars, with higher combustion temps really make it hard to diagnose as they generally CAN and WILL burn the oil cleaners and we have thinner oil that will burn off easier. Converters will self clean to a point , hence the part about EPA claiming converter damage but generally in practice its crap argument, and if pluged you can use a product called cataclean from Mr Gasket to help clean off said contamination after repair or replacement.
Also if your tuning an older higher miles engine and keep fighting KR it can be caused by preignition/detonation from oil migration into combustion chamber. Couple of guys I met locally , father and son , have me helping beefup/build thier engines. One goes in sons car he got from grandma 04 GTP with chipped piston. Dad has an engine, supercharged and it has chipped pistons, but his plan is to install a Buick in his sandrail.

Well - didn't know about cataclean, or maybe it wasn't around when I first needed it.
I have an 03 Regal LS, so a non-supercharged 3800 Series II.
Original converter plugged up at 135K, +/-.
I had the muffler shop put in a "re-certified" unit, which means "used but tested", I suspect.
I forget - it ran 50-70K miles? Plugged, I had an aftermarket converter installed.
Around 260K miles it started throwing a code (410?) for low cat efficiency.
A recent change in driving habits - harder pulls, up some decent hills - and it stopped throwing codes. The CEL actually went out, I checked codes and it is clear.
So, driving pattern matters.
The motor runs fine, does prob use more than a quart per 1000 miles. Lots of times I don't change it until the reminder light comes on.
Yes, bad boy. Oh, well.
Currently 275K miles, runs great. Original trans has been crappy for over 100k miles. Still works well enough.
Yes, it has been overheated, but not too bad - first time an elbow failed, I only noticed because I wasn't getting any heat from the heater.
Dumb SOBs that changed it didn't do the second elbow. When that second elbow failed, I had two new metal ones installed. (on the road with family and no toolbox)
- so - give it clean oil and trans fluid once in a while, run the heck out of it, and add oil when needed.

Originally Posted by FordMan77

Also, if you're not visibly loosing oil from a leak (check the front and rear manifolds for sings of oil dripping, which would be a valve cover gasket), then don't forget to change the PCV valve. Could be gunked up causing excess pressure in the crankcase.

When I replaced the engine in mine, I got a motor with around 140K on it for $300. Add in gaskets, coolant and small parts I was right around $500. It pays to shop around places like RockAuto, Ebay, Amazon, etc. I swapped the motor in my garage with no lift and basic hand tools (with some air ones thrown in for speed). Just removed the hood and pulled it out the top.

how much time did you invest in that process?

Did you ever doubt your decision of not spending the $700-1000 for labor at a trusted shop while you make more money doing what you do?

I guess if I make $15/hour doing what I do, then that's $120/day or $600/week, and a week is what I will need to do it myself, then having someone do it for me makes more sense, especially since they do it in half the time and that'll mean half the time of rental for the replacement car that I will get in the meantime

Originally Posted by Scottydoggs

qt loss between 3,000 mile oil changes is normal as per gm. sure your not leaking it?

screw that oil life thing, set the trip change it every 3 to 5,000 miles depending on the oil you run.

i put no miles on my car per year, maybe 5,000, so i just change it twice a year.

That significantly lowered my worry-o-meter, appreciate it

Originally Posted by coolone

You mention oil change every month but you don't mention miles. Only in your hypothetical, theoretical scenario do you mention miles.

You need to be more specific as to how much oil is being lost. Then you need to be sure there are no leaks, or are you burning it. Compression test will tell you a lot but isn't an end all. Could be simple as valve seals. And yeah, if you're burning a quart a week (500 mile assumption), then no, you don't ned to change oil every 2000, just the filter, if that. But if your burning that much oil 1qt/500 miles, you aren't going to be using that engine long.

That said, there's no benefit to a rebuild over a JY engine. You need to change standard oil 2000-3000 miles, anything higher is no go. Synthetics especially pure, can go longer intervals before it breaks down. Mobile 1 (Synthetic Blend) is changed every 5000-6000. New filter every time. Only way I'd do a rebuild, machine shop special 3800 is if I were attempting to go where no 3800 went before, lol.

I'm sorry about the confusion, I put around 50 miles/day or 1500-1800/month.

And, for the oil I'm loosing, it's about 1qt/month (or you can say per 2000 miles and much better than the 500 you mentioned).
BTW, do you have any idea about the cost of a compression test or valve seals replaced? just a rough number.
You mentioned something kind of weird in your second paragraph, i.e., changing filter without changing oil!!
I use GTX full synthetic high-milage oil and the highest end thing walmart has for filters, so I do the changes at more than 3000 miles intervals (typically 4000-6000).

I'll take your advice in not rebuilding in the future (about a 100 years or the obsolescence of my kind, whichever comes first, lol), but putting a remanufactured one with a long warranty.

Originally Posted by MonzaRacer

Ok so lets get some basic ideas out in the world again. and some basic info on oil.
Conventional oil, non blend WAS oil that was cracked from crude oil THEN each manufacturers additive package.
About 10+ yrs ago the EPA started pushing for lower phosphorus and zinc levels (high pressure antiwear additives) so the manufacturers had to add come up with ways to beef up the high pressure capabilities.
THUS they came up with synthetic replacements.
Synthetic means the molecules are engineered in a lab rather that using raw element based like phosphorus and zinc. Synthetic oils are produced the same way, engineered rather than "cracked" from crude to base oils.
Thus when engineering the molecules they are all identical and the characteristics are designed in.
Synthetics have engineered to take the heat and stress and synthetic additive package for foaming, dispersants, detergents etc.
The bad thing is the replacements for zinc(zinc dithiophosphate or ZDDP) and phosphorus cant really be replaced as easy. Blended oils dont actually work as well thus making Brad Penn and Comp Cams high zinc oils useful for older car owners.
Roller cam engines have LESS issue but pitting and wear can still result.
Supposedly the EPA tried "these additives contaminate converters thus they need reduced/removed" then converter makers and OEMs got riled up on that, so they went to "its better for the environment sue to personal oil changes and improper disposal" which well over 90% of old oil IS recycled and very little is "dumped" anymore. I am sure every town had an old rock road just outside of town the county "oiled" so they dump their oil their too. Road oil is a lot different.
Anyway as the oil detergent/dispersant/anti-wear package was perfected, namely to deal with heat and wear and tear, gas reformulation to unleaded, etc the manufacturers and oil companies hit a "happy spot" and advertised 3 month/3000 miles and it worked as the average mileage WAS that.
Now everyone talks about better machine processes, better materials, yada, yada,yada.
Most of the wear on older cars came from carbon buildup, gasoline dilution from carburation, and some from parts getting better. But saying a straight machined cylinder in the 60s is straighter than the 2000s, sorry thats BS.
Now have they gotten better at using less material and DESIGNING stronger castings, sure but now we dont get decent engines that we can bore out a bunch to make bigger. Now we get engines that can only be over bored 10 or 20 thousandths.
When I started doing maintenance plans for businesses and car owners. I always look at severe service intervals rather than "normal" chart as no one is normal.
For granny who parks car and drives every other week to go to store and such, 3month/3000mi is bit overkill as they rarely HIT the 3000mil mark.
But at least every 6 month works.
But some of these car makers are claiming 7500-10000 mi intervals and some people just dont drive that much, but many drive a lot more. I was offered job with old employer but job is like 100mi one way. 5 days a week.
That would be 1000mi a week.
Oil lights work off time, heat,mileage,load algorithm.
Chose an oil/brand/weight that is accepted and stick with it.
Change oil and check in same spot at least weekly and not it with miles. Oil consumption will be two ways, continuously ie burning oil, generally shown with fouling plugs, smoking, etc.
OR from age/wear/tear/breakdown. and will usually happen all in a very short time. This is from oil reaching a limit of dilution/contamination/breakdown.
Many engines have this point and it should be a factor when deciding on oil change intervals.
BUT run an oil change, note when it gets low. I do know you can drive a qt low but you need to note oil level daily if you dont add that first qt. ALSO if you do add that 1st lost qt not how long it takes till it gets low again.
Proper inspection and evaluation depends on observed inspection. Oil level USED to stay high as fuel diluted it THEN when it got high enough the engine would stat consuming the diluted fuel, and as the level gets lower the oil temps go up and fuel boils off.
MOST oil consumption in current engines starts happening after 250-500 miles after new oil gets mixed with left over old oil, and additive package stabilizes in the sump contents.
Keeping proper records help deduce WHAT is going on. A steady diet of oil means mechanical or lubricant issues like worn parts or oil brand/type/weight not suited to your specific use.
You can use different weights, brands, etc.
Blended oil to synthetics, vice versa, or going to next heavy weight, truck oils, what ever.
Keep records and change one thing at a time. Had a customer who wanted Castrol in his car so he brought it. The car started using oil at about 60k, so I offered to change him up and see what happened, had him come by shop every week for oil checks. Switched him to Shell Rotella T, and first oil change at about 2000 miles the filter was HEAVY, the oil was filthy. 3rd oil change car stopped using as much oil.
Now for the other part, we did a tune up at same time, and I did compression test on couple cylinders. So when it quit using oil, the compression actually came up by 15 lbs.
Turns out the owners driving style didnt work using Castrol. So at the shop I worked at we had "Quaker State" which since I found out back then that Shell oil company owns/makes QS and Pennzoil and we started using shops 10w30 and he hasnt had issue since as he kept using same oil even when that shop shut down.
Oils like fuels, tires, even cars need finessing by trial ans error. First figure out if its using, leaking or normal consumption.
Devising a plan to WATCH, and record symptoms may take a bit but going from there is the way to properly decide if the engine is broken, damaged and running or ready to fail.
Crudding up the plugs is generally rings or valve stem seals. BUT on the newer cars, with higher combustion temps really make it hard to diagnose as they generally CAN and WILL burn the oil cleaners and we have thinner oil that will burn off easier. Converters will self clean to a point , hence the part about EPA claiming converter damage but generally in practice its crap argument, and if pluged you can use a product called cataclean from Mr Gasket to help clean off said contamination after repair or replacement.
Also if your tuning an older higher miles engine and keep fighting KR it can be caused by preignition/detonation from oil migration into combustion chamber. Couple of guys I met locally , father and son , have me helping beefup/build thier engines. One goes in sons car he got from grandma 04 GTP with chipped piston. Dad has an engine, supercharged and it has chipped pistons, but his plan is to install a Buick in his sandrail.

Thanks much for the insights and the info.
When I owned my first car, I do not remember really thinking much about the brand of oil/filter to use. For the last couple of years on this car, I happened to have been using Castrol GTX high-milage 5W30. But, after reading what you have said that comes from the wisdom of the years. I will try something else and update here.

It's just like when I was a smoker and I used an electric machine to roll my own, whenever I was out of tubes or tobacco that I usually get online and takes time, I run to the store to get a pack of the kind that represent a compromise between low price and shiny colors.
It looks like choosing different synthetic oil brands (different additives) for different engines is a thing after all.

Sounds like everybody's spot on, but I just wanted to throw in my experience on the engine.

Bought it with a hydrolocked engine with a giant crack in the block. One owner vehicle, maintained correctly, oil changes and all service receipts documented. Unfortunately, whoever serviced her lower intake manifold "messed up" causing the engine to dump coolant into lifter valley and hydrolock cylinder 1 which shattered the connecting rod, hit it's neighbor and broke and then hit the block, cracked it, seized and warped/cracked EVERYTHING (including cam and heads).

I decided to rebuild an engine from the junkyard. Tore down and checked specs myself, sent in to machine shop for 20 thou overbore. These engines have push fit connecting rod bearings, so they'll have to do that unless you want to invest in that equipment. I re-assembled everything and pieced together ALL of the components from scratch, re-assembled everything, replaced all tty bolts and it STILL cost me around $1500. (complete valve job drove the cost WAY up)

I have been driving on it for about 2000 miles. Took it in to see if I needed a CASE learn and the dealer mechanic hooked up his tool, laughed, and showed me the fuel trim and engine data. It was between 0 and 1% error (nearly perfect) and that it didn't need a case learn. It was by far the best 3800 he had EVER seen. The compression is at stock values.

Basically, my advise is it depends what you are looking for and are willing to pay. My rebuilt engine has better gaskets and internals than factory and all clearances are back to stock. This engine could last 300,000 miles. A junkyard or "low mileage" engine still has stock gaskets, and there's no guarantee.

If I could do it again, I would save my time and buy one re-manufactured by the pros.

Good luck!

FWIW Audi's are 1 quart at every 5K and typically.. they can burn more than that if you buzz around in sport mode or need the carbon and crap cleaned off the valves because of direct injection.

My rule of thumb: Change your oil at every 3k and your engine will clean itself from the inside. In say 20K miles.. it'll look great inside. Change at 5K if you care less about your engine and are willing to see some build up inside if you ever open it up. I've put quite a few miles on and seen both of these a bunch of times. The 3800 isn't a tight tolerance, super clean motor. What it is.. it's a great running motor that with proper maintenance can live a very long and happy life while getting some awesome mpg for the era of motor that it is.

As far as overhauling the motor yourself versus paying someone - there are factors...
For example, you may or may not be in a position to do more of "what you do" to make the money to pay for the overhaul.
Also, if you have a decent workspace and can be without your car for a while (or buy a used motor and overhaul it while still running your existing unit)
My 03 Regal LS is now gone - still ran fine, but I already had a replacement and it was time for it to go. It was hit while parked, and ins company is totaling it. Good timing.
Poor thing, I did feel really guilty. I bought it used in 03 and had put over 230k on it myself.