Loosing coolant and oil in my 2001 Grand Prix GTP

**zguy** · 08-01-2015

Hello. I have owned my 2001 GTP since 2006 and I bought it used with 35,000 miles. It now has 144,000 miles on it. I originally owned a 1997 GT that I bought new. I bought this one and sold that one back in 2006. It has had all of the typical Grand Prix issues that I am aware of. I have listed all of the repairs to date below. I did not include normal wear items like tires and brakes. The car runs great and idles perfect. I have used synthetic oil since I got it up until my last oil change. For the past year or so I have been noticing excessive oil usage. About 1.5 quarts or so every oil change. There are no visible leaks on the garage floor or around the valve covers or intake manifold that I can see. My oil pan has some seepage on it but not enough to drip onto the floor. Where is this oil going? I don't see any smoke on start up or while running. I switched to regular motor oil because I read that synthetic will make its way through any worn out seals, parts, etc. Switching oil types has not made any improvements as I am still loosing oil at the same rate. Any ideas?

In addition, I have been adding coolant monthly. About a 1 cup or so. There are no visible leaks that I can see. Where is this coolant going? I don't see white smoke from the exhaust. Repairs to date are listed below.

---------------------------------------

Leaking tail lights (replaced with used original ones from junk yard at 90,000 miles)
Leaking head lights (replace with aftermarket parts at 133,000)
Rusted front sway bar (replaced with Dorman part at 125,000)
Front wheel bearings (Replaced at 108,000)
Lower control arms (Replaced at 108,000)
Struts (all four replace at 108,000)
EGR valve (replaced at 133,000)
Valve cover (replaced by dealer under recall around 50,000 miles or so. I think it was the front one but I don't recall)
ABS module (had rebuilt at 85,000)
Driver's side window regulator and motor (replaced at 135,000)
Steering rack and pinion (replaced at 118,000)
Rear brake proportioning valve (replaced at 136,000)
Coolant elbows (replaced with Dorman aluminum ones at 135,000 miles)
Coolant level sensor (replaced at 100,000)
Thermostat replaced (110,000 miles)
PCV valve (replaced at 100,000 and 135,000)
New GM Spark plugs and wires (replaced at 100,000)
Mass air flow sensor (replaced around 115,000 miles with rebuilt one)
Heater motor resistor (replaced around 85,000)
Lower intake manifold gasket (replaced by dealer around 85,000 miles or so)

**bobc455** · 08-01-2015

If the lower intake gasket was replaced by the dealer, did they use another plastic gasket?

I did a LIM gasket on a '98 Park avenue in about 2005, and re-did it a couple of months ago (using a metal gasket this time of course)

-BC

**zguy** · 08-01-2015

I need to check my receipts. I am hoping there is a part number that I could use to determine what type they used. Could the LIM cause the symptoms that I am seeing?

**Turbocharged400sbc** · 08-01-2015

its also possible its the rear block covers gasket.

if you have an inspection camera you can fish it through the bellhousing hole below the coolant temp sensor to see if its leaking. the coolant usually dries/evaporates before it gets all the way down the block. but youll see either green or pink crusting.

**zguy** · 08-20-2015

Just had the car inspected at the dealer. They said that there are no visible leaks except some tiny seepage from the front valve cover gasket and some around the oil pan. They suggested that they pull off the supercharger and see if there is oil visible in the valleys which would indicate a LIM gasket. Normally some seepage is visible from the gasket but mine isn't showing anything. They want $400 to pull the supercharger off to inspect including a gasket to put it back on. This of course would not include the replacing the LIM.

At this point do I just order the parts to replace the LIM and assume that is the case when I get it apart?

I still don't understand where all the oil and antifreeze is going. The oil does not show signs of coolant and neither does the cooling system show oil. I am loosing between 2 and 3 quarts of oil every oil change. I tried conventional oil with this last oil change but it did not make a difference so I will go back to synthetic next time. I am also loosing about 1 cup or less every month for coolant.

**QUICKSILVER462** · 08-20-2015

If your valve stem oil seals are bad, then a lot of oil could be lost and no signs will be evident.

**zguy** · 08-20-2015

Originally Posted by QUICKSILVER462

If your valve stem oil seals are bad, then a lot of oil could be lost and no signs will be evident.

I can see that. Would a compression test indicate bad valve stem oil seals? I suppose a failed result would indicate an issue but not necessarily that specific part. E.g. valve stem oil seals, piston rings...

I suppose that would not explain the coolant disappearance though.

**zguy** · 08-24-2015

I am going to go ahead and order parts in order to replace the LIM gasket with hopes of resolving my loss of coolant and oil issue with my car. There are no visible leaks anywhere. I am concerned about the loss of coolant as I can't quite understand where it could be going if not leaking. Could it be pooling under the LIM and then being burned off? I can't imagine it going into the cylinders or the oil for that matter as one would produce white smoke and the other would show up in my oil.

Either way I think it is cheap insurance to change the LIM regardless. I found a very useful thread which I listed below. I looking to get clarity or opinions on whether or not the AC/Delco LIM gasket is a must. I know I want a metal one but is that only available with AC/Delco or does Felpro make one. I am considering this kit.

http://www.grandprixforums.net/threa...ntake+manifold
http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER

Thoughts?

Is there anything else I should be changing aside from gaskets? E.g. Lower intake manifold gasket, upper plenum gasket, thermostat gasket assuming I remove it. I just changed the coolant elbows with metal ones last year. What about the water pump? Should I mess with it? It's original. I may do the valve cover gaskets while I am at it. The wires and plugs were replaced about 40,000 miles ago.

Also, will I need a special tool to disconnect the fuel rail?
http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER

Thanks...

**bobc455** · 08-27-2015

Felpro makes a metal gasket, and I've used it with no problems, but if the AC Delco is availble then I prefer that.

That little tool will make it much neater and cleaner than any other way to remove the fuel line. It's probably also available at your local auto parts store, nothing fancy (but well worth the price!).

Some kits come with injector o-rings but I've never bothered.

Valvecover gaskets are probably a good preventative fix while you're in there and have the tools out.

Plugs, wires, thermostat, etc., are not necessary unless you're having problems. Be careful not to break the little wire holders under the front valvecover.

**blueguy** · 08-27-2015

If you're there, I would replace everything. It'd make life so much easier just ripping out all the old crap from the get go and replacing with all new stuff. It's not like a set of wires/copper plugs/t-stat are expensive...it's like $50~ or so for all of it.

**2004l67** · 08-27-2015

If your engine bay is clean, you should be able to see the ends of the LIM gaskets with a flashlight enough to see if they're plastic or metal.

You could do a coolant pressure test too to check the rest of the system if they look good.

**zguy** · 08-28-2015

Originally Posted by 2004l67

If your engine bay is clean, you should be able to see the ends of the LIM gaskets with a flashlight enough to see if they're plastic or metal.

You could do a coolant pressure test too to check the rest of the system if they look good.

The ends of the gasket look white. Like white plastic from what I can tell. I also see some orange sealant or RTV. My guess is that the LIM is plastic? I just checked and the LIM and rear valve cover gasket was changed in 2011 which is more recent than I thought. I would have had about 95,000 miles or so on the odometer. Not sure what the dealer would have used back in 2011. Maybe it was metal? Not sure. Could the gasket be bad 4 years later and only with 45k miles?

**bobc455** · 08-27-2015

By the way, I didn't read that procedure but consider adding some pipe plugs under the throttle body.

-BC

**zguy** · 08-28-2015

Originally Posted by bobc455

By the way, I didn't read that procedure but consider adding some pipe plugs under the throttle body.

-BC

What are pipe plugs and what do they do if added?

**bobc455** · 08-28-2015

There are coolant passages to heat the throttle body in extreme cold weather. Generally considered unnecessary, so blocking these passages will prevent deterioration of the intake manifold by the coolant.

**zguy** · 08-28-2015

Is this true for both the supercharged 3800 and the naturally aspirated one?

**Scottydoggs** · 08-28-2015

not true really at all.

sealing those ports on a n/a engine will keep the upper intake from failing and dumping coolant into the lim and hydro locking the engine. its a common failure in the n/a engine.

this dont happen on the s/c engines. but we still seal em off. if you do seal them off you want to open the side cover and hog out the water passage to help get the coolant to the back side of the lim and head faster.

ports sealed. i used dimes and quick steel. you can drill tap and use plugs if you like, rtv'd dimes have been used too.