A few issues

**Cummins97** · 03-18-2012

I have an 01 GP 3.8 n/a. It has a few issues that I want to get fixed so I can reliably drive it.

P0420 - Catalyst efficiency, bank 1 - Is there any way to know exactly what causes this code is other than just changing O2's, then the cat or vise versa? It does have an exhaust leak at the downpipe connection that I plan to get fixed tomorrow. Would that alone fix the code/dying all the time?

It also has oil in the anit-freeze. Do these cars have an oil cooler that could also be the problem or is it for sure a head gasket?

It also wont shift into overdrive. What are my options here?

Any help with these issues would be greatly appreciated! Thanks!

**MoarkatsINmuhtrailer** · 03-18-2012

Probably the leak causing the code.

The head gaskets are never the problem. Being an n/a, you'll want to replace the lim gaskets and the complete uim. Most auto parts stores sell the Dorman intake manifold for around 125. It comes with the major fix to the leaking problem in the egr tunnel. The problem being that the oem egr tube sits too close to the plastic uim, causing it to create a hole into the coolant passages and in turn, into the lim and engine.
Get going with replacing this stuff quick else you're going to be looking at a locked engine when it fully goes out.

The fix with the new uim is a new, smaller diameter egr tube, this keeps it away from the plastic so it doesn't blow out again.

**Cummins97** · 03-18-2012

Ok good I'll try the gasket to fix the code.

The lim gaskets and the whole uim would cause oil to be in the anti-freeze? Not doubting you, just making sure you didnt read it backwards by accident!

**Scottydoggs** · 03-18-2012

Originally Posted by Cummins97

It also has oil in the anit-freeze. Do these cars have an oil cooler that could also be the problem or is it for sure a head gasket?

It also wont shift into overdrive. What are my options here?

are you sure you have oil in your coolant?

trans fluid in your coolant sounds more like the way it should be. there is a trans cooler in the radiator it cracks and coolant gets into the trans and yes kills it, check your trans fluid level and color. could be why you have no 4 th gear, or the 4 th gear hub stripped.

when the lim gasket goes bad the coolant gets into the oil in the engine and you get milky looking oil in your engine.

**MoarkatsINmuhtrailer** · 03-18-2012

I read wrong -_- lol

**Cummins97** · 03-18-2012

Lol it happens

I'm almost positive it is oil yes, but it could be trans fluid i guess. I haven't checked it yet as I just got the car back from the ex. I will have to check the trans fluid to confirm what it is. I pulled the cap to check the anti-freeze and seen the gray/black gunk on the cap, then fingered the rad and it came out the same way as the cap. It seemed more black than anything so I assumed oil and bad hg. Hopefully its the rad/cooler rather than gaskets!

**Scottydoggs** · 03-18-2012

that sounds like dex sludge. take a pic and post it. you may just need a coolant flush. to deal with that part of your problems.

you can bang on your cat, listen for rattling inside it if so the cat is bad. if you hear nothing try the o2 sensor.

**MoarkatsINmuhtrailer** · 03-18-2012

I think it's just the sludge that occurs when the dexcool and green coolant get mixed. Do a coolant flush and you'll be fine,

**Scottydoggs** · 03-18-2012

Originally Posted by 99pgpgt

I think it's just the sludge that occurs when the dexcool and green coolant get mixed. Do a coolant flush and you'll be fine,

its air that makes the sludge form in dex.

**Cummins97** · 03-18-2012

ok I'll get a pic of it in the am. I'll check the cat too. I really appreciate all your replies guys, thanks!

**Fivefingerdeathpunch** · 03-19-2012

we have a oil and trans side tanks on the rad, so it could very well be oil.

**Scottydoggs** · 03-19-2012

Originally Posted by Fivefingerdeathpunch

we have a oil and trans side tanks on the rad, so it could very well be oil.

i was not aware the GP's had a oil cooler in the rad, i haven't noticed extra lines on my regal. should you have this option, yeah it could be oil, but it still could be dex sludge, lets hope so any way, a flush is better than a new radiator.

**Rico** · 03-19-2012

Originally Posted by Fivefingerdeathpunch

we have a oil and trans side tanks on the rad, so it could very well be oil.

I have a stock rad, holding it right now and I can only see the quick disconnects for the trans fluid cooler. Was this an option or something? This rad came from my 2000 GT.

**Cummins97** · 03-19-2012

Ah geez and I was getting excited about it possibly just needing a flush lol. I guess I'll just take a pic of it and post it to see what y'all think.

**Cummins97** · 03-19-2012

Ok guys, here's the rad cap and what I wiped out of the red neck.
[IMG]

[/IMG]

I looked and looked for oil cooler lines and all I can find are 2 trans cooler lines and the rad hoses, so I'm gonna have to say no oil cooler on this car. I checked the trans fluid and it was at normal level and looked in good shape. The rad is low on fluid and from what I can see of it, it looks kind of orange ish green.

**MoarkatsINmuhtrailer** · 03-19-2012

do a coolant flush

**Cummins97** · 03-19-2012

Originally Posted by 99pgpgt

do a coolant flush

In the process now!

**Cummins97** · 03-19-2012

Ok, I got it drained and flushed out till the water was clear. I'd like to clean it out with something other than just water. should I use a powder laundry soap, the prestone rad cleaner, or any suggestions? Should I go ahead and pull the t-stat and run some sort of cleaner or am I good?

Here's a pic of the fluid that came out. There wasn't a whole lot that came out.
[IMG]

[/IMG]

Also, while flushing the system I noticed the rear fuel line connection at the rail was a little wet. Looks like I gotta go to the parts store and see if I can find a new quick disconnect seal or whatever it's called.

**Scottydoggs** · 03-19-2012

dont use soap or anything like that. if your dead set on a product get some radiator flush treatment, from like prestone or some other name brand.

heres what to do.

remove the thermostat,(put the housing and hose back on) remove the upper rad hose from the rad, open the rad cap, put hose in rad cap opening, turn hose on, start the car, and all the coolant will pump out the upper hose to a bucket on the ground under the upper rad hose. run the car till clear water comes out the hose.

turn the hose off, run the car some more so more water comes out.

put it all back together and dump a gallon or so of full strength green coolant of your choice. bleed the air out and done.

**Cummins97** · 03-19-2012

Ok, I'm gonna do that, put a new t-stat in it, fix the exhaust leak, fix the fuel leak then drive it for a while.

I got to lookin around and found a motor and trans from a 98, 3800 series 2 and trans for $300. They will both work in my 01 right? If so I'm thinkin project time

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