Oil/coolant smell at stops

[fisdadsbonneville]

I just got my 2005 GXP on Friday and when I test drive it I could smell a little oil or coolant smell coming through the vents when sitting at a stop. When driving I don't smell anything. The low coolant light came on a couple of times but I topped off the reservoir and that was that so far. I've put about 500 miles on the car this week and it runs and drives great other than this smell and some interior lighting issues. I peaked under the car tonight after noticing a nickel sized spot of what appears to be oil on my driveway. It looks like the sway bar, cradle and oil pan are greasy/oily. Not a lot though. I'm assuming an oil pan gasket and I can see a bit of sea page around my rear valve cover gasket. Should I worry about repairing this stuff or just let it ride until I start going through oil? Also I know that both of these are common issues on this engine. Are there any other likely leak spots that I should eyeball? Are there any common coolant leak issues besides head bolts and head gaskets that I should look for while I'm at it?

[CMNTMXR57]

N*'s leak coolant and oil. It is their mission in life.

Coolant is probably coming from the freeze plugs not fully sealing until the engine fully warms up. So it seeps coolant overnight, drips down the engine block and onto the transmission and exhaust cross-under pipe. It then eventually gets burned off from the heat of the engine/trans/exhaust. GM coolant seal tablets work great here.

Oil is 99% most likely the cam covers (valve covers) as you have noted. The bolts are only torqued to 7lb/ft, so over time, with heat cycling, they loosen back up, causing oil to seep out. Sometimes even the gasket goes bad too. If necessary a new gasket, and then tightend the bolts, with a little loctite, say to 10 lb/ft is what I did and they never seeped again. The rear gasket is a PITA to replace because getting the cam cover off between the engine and that large, main wiring harness, is an excercise in learning new levels of profanity. It also will require removal of the EGR system to get it out of the way. Not difficult, just one more thing that needs to be done.

[bobgto65]

If the coolant leak persists you can put 6 GM coolant pellets in your anti-freeze or a similar amount of Bars Stop Leak.

[fisdadsbonneville]

How hard is it to change the freeze plugs? Is it worth the effort?

[CMNTMXR57]

Difficult and no.

Just do the coolant pellets as both Bob and I have told you. They work.

[fisdadsbonneville]

Thanks for the heads up on that. I'm one of those morons who will usually replace anything that isn't 100% over and over again to keep it 100%, but this n* is a pricey little girl so I think I'm over that thought for now.

I am no longer smelling coolant. It turns out that I was just smelling oil. I looked up under the car and there is a black bracket going beside the oil pan that appears to be covering the exhaust. Oil is dripping off of that between the oil pan and the tranny pan. I'm assuming that this is most likely the oil pan gasket, but is there anything else I should be worried about? The only northstar tech who isn't a dealer in my area said something about a pressurized something or other that goes bad too. Does anyone know what this might be?

Also, the same tech quoted me $1800 to pull the motor, change the pan gasket, pressurized something or other and full top gaskets as well as re-stud the motor and replace the head gaskets. I thought that was a pretty fair price really for all of that bs. What do you guys think? I don't have a head gasket or overheating issue at the moment. Would I be better off to just fix my leak and let it ride for now? The Dealership has quoted me between $720 and $1050 to do just the oil pan gasket.

[CMNTMXR57]

Yes, that protects the cross-under exhaust from the front bank.

Cam covers, oil cooler lines, etc... That is where most oil leaks come from on N*'s.

I wouldn't spend to pull and restud it if that work isn't needed. You're trying to kill ants with a flame thrower. Just replace your cam cover gaskets and tighten the cam cover bolts down with some loctite and see if that helps. Cooler lines you will never stop from leaking. That is GM's quick disconnect design. Replacing them, the new ones will leak tomorrow... I have resorted to on mine as well as higher mileage GM vehicles that came in for this when in service... Just JB Weld the joint.

[fisdadsbonneville]

Yes, that protects the cross-under exhaust from the front bank.

Cam covers, oil cooler lines, etc... That is where most oil leaks come from on N*'s.

I wouldn't spend to pull and restud it if that work isn't needed. You're trying to kill ants with a flame thrower. Just replace your cam cover gaskets and tighten the cam cover bolts down with some loctite and see if that helps. Cooler lines you will never stop from leaking. That is GM's quick disconnect design. Replacing them, the new ones will leak tomorrow... I have resorted to on mine as well as higher mileage GM vehicles that came in for this when in service... Just JB Weld the joint.

JB Weld... I love this guy! lol. That's not really my style, but I'm also not a fan of throwing away money. Do you know if there is a how to or a recommended repair manual for the n* in our cars? I'm wanting to change the oil pan gaskets and the cam cover gaskets. While I have the subframe down anyway I'm hoping to replace the motor mounts while I'm at it. I have a little play and my shift from 2nd to 3rd is a little wonky. Not hard, but it seems to bumble around on that shift.

[CMNTMXR57]

Again, cost vs. benefit ratio. I too am not a fan of it and would not do it on a brand spanking new vehicle that came in or on a pristine car that is meticulously maintained, but on a 50k, 75k, 100k car that has a filthy undercarriage along with normal wear/tear/aging, and who the owner really doesn't care, it (JB Weld), works and is CHEAP. I did it on mine, and never had a leak again. I sold mine with 80k and a coating of shiny, dried JB Weld on my cooler line fittings, was the least of the ugly things on the underside...

Your options;
1) Replace the lines with GM replacements and be leaking again the next day
2) Make custom, non-flexible, fittings in both the line and where they go into on the block/filter assembly/radiator/wherever, which could get costly to fix a minute "annoyance" type problem
3) JB Weld, again, maybe not the solution you want to hear, but it's dirt cheap and gets the job done. Who besides you is going to be looking at your oil cooler lines??

Haynes: http://www.haynes.com/products/?searchT ... e&x=10&y=9

I think Chilton has one also. Your other option is GM SI (Service Information), Discs if you can find them online.

[fisdadsbonneville]

Do you have a pic of the oil cooler lines that you are referring to so I can coat them while I'm down there?

I wasn't sure with the n* being an oddball engine in the bonne if it would be in the Haynes manual or not. Thanks!

[CMNTMXR57]

No. I never really took a lot of pics of the Bonneville, much less stuff like engine/oil cooler lines. It was my DD/utility vehicle and all I cared about was that I kept it running.

As you will learn, the sole purpose of the N*'s existence is to leak stuff. Kinda like an old Chevy Big Block. Chasing each little leak will drive you mad.

[fisdadsbonneville]

The burning smell is what is driving me mad.

[CMNTMXR57]

I know. It's frustrating. Again, this *dang* thing is like an old school Big Block. It doesn't burn it, but it likes to leak it. Where I really suspect your issue lies, is in the cam covers/cam cover gaskets. Every one of us I think (at least those that have checked), have had this issue. I did on mine, and even the LC3 in my "V" all had loose bolts. And to top it all off, my VVT actuators on that like to leak also...

Even if your oil cooler lines leak, they will only drip down on the ground. Not anything hot like exhaust components.

[fisdadsbonneville]

If I hadn't been in love with this car since I saw the concept I would have gotten rid of it by now, but this car is just freaking awesome! Sadly, in Indianapolis there is only one shop outside of the dealer who will work on the n* motor and he's not cheap. I suppose that I will have to figure out how to drop the subframe and replace the mounts, oil pan gaskets and fix the cam cover gaskets on my own. I'm pretty sure that the cam covers won't be so bad, but the rest of it sounds like a pita.

I'm tempted to just plastidip the entire motor and hope that it holds up lol.

[1oldman]

......... You're trying to kill ants with a flame thrower. Just replace your cam cover gaskets and tighten the cam cover bolts down with some loctite and see if that helps. .........

What color of Loctite? Green? - BC

[CMNTMXR57]

Blue I think.

[bobgto65]

I totally agree with CMNTMXR57. Try tightening up the cam cover bolts first and don't spend a lot of time dropping the sub-frame to change the oil pan gaskets, use the JB weld on the collant lines, and see if that solves your problem.

[cbp1945]

Gents,
I appreciate your posts. I am working on a foul oil burn odor that I smell at stops. I just picked up my 2005 Bonne GXP (125K miles) from my local Silver Spring Sport Chevrolet Service Department. (My Pontiac dealer closed shop a couple of years ago.) The shop has cleaned the engine and added a dye to the oil to help diagnose the source of the oil leakage. Initial diagnosis is that the valve cover gaskets do leak. If the oil pan shows excessive leakage, then my problem solution is more difficult (costly). I was told that oil pan gasket replacement will require dropping the engine. (Sounds to me from previous posts that the engine doesn't need to be dropped, but perhaps some frame members do.)
Anyway, I'll have my GXP back in the shop in a few days, and now expect that I'll be having the valve cover gaskets replaced. ($1400). I'll follow up with some posts. In the meantime, I would further appreciate any posts that would help me.
Thanks again for posting.
Regards,
CBP1945
PS. I've had those oil cooler lines replaced earlier this year.

[CMNTMXR57]

Cam cover gaskets as well as the torque spec (7lb/ft if I recall), are the two major issues. You torque them down and a few heat cyclings and they're loose again. I did the loctite as mentioned above and went 10 lb/ft and never had a problem there after.