PontiacBonnevilleClub.com

Hey guys, it's been some weeks, but mostly because I've been broke these days! So, I went to add a quart of oil (did I mention that my car burns a quart of oil every 5K miles or so?? I do like 80% highway driving, and a lot of it. I've put 11K miles on in the past six months - is this normal??!), so I went to buy my quart of Mobil One oil, and figured since I was under the hood I'd have a look. Lo and behold, the overflow reservoir for the coolant was empty!!! Furthermore, I checked the cool radiator after work today, and it is not full to the top like it should be.

So where do I look?? There are no obvious leaks, no puddles after being parked overnight, oil pressure gauge reads good and strong...and of course my fear is that the coolant is inside the oil - but that fear is not legit because neither the dipstick nor looking into the oil fill show any signs of coolant being in there, so where did it go???! I had both coolant elbows replaced when I bought the car in February, and they don't appear to be leaking, so I'm scratching my head wondering where this coolant ran off to. I hope to take it to my mechanic tomorrow, but I'm not sure if he can squeeze me in or not. Suggestions?

I'm in a bit of a pinch, because the Bonnie needs new tires all the way around, and has several other minor problems (i.e. shaking when breaking, for one), but this coolant leak alarms me and thought I'd run it past the best Bonneville source on the 'net. Thanks all!

I'm not the best source, but someone who is should chime in.

Seems you have all the possibilities ruled out. My only thought is coolant loss when hot and not showing puddles etc after driving

Bad UIM. The EGR port burns through and it gets sucked into the motor and burnt off. Could also be LIM gaskets which should be done when the UIM is ....replaced.

Oil burning, 5000 on a quart is not bad, but check / replace the PCV valve. They are pretty cheap. Could also be a leak. When was the last time you inspected and cleaned the underside?

myfirstbonnie wrote:Bad UIM. The EGR port burns through and it gets sucked into the motor and burnt off. Could also be LIM gaskets which should be done when the UIM is ....replaced.

Oil burning, 5000 on a quart is not bad, but check / replace the PCV valve. They are pretty cheap. Could also be a leak. When was the last time you inspected and cleaned the underside?

He doesnt have the AL one? Hes an 05.

Nope, he still has an L36, GM never upgraded it, and the Bonne never got the L26.

00Beast wrote:Nope, he still has an L36, GM never upgraded it, and the Bonne never got the L26.

oh ok.

Correct me if I'm wrong, but coolant leaking from the EGR stem would definitely coincide with my very POOR fuel economy the last two tanks. I'm a freak when it comes to watching my fuel economy, and I saw it drop pretty significantly in the last two fillups (i.e. from +/- 24MPG to about +/- 19MPG total mixed hwy/cty). So, if coolant was getting in there and being burned off, that would fit with what you guys are saying as well, right? Or......does it not get into the piston chamber?!

Smell the exhaust (Don't stick your nose in it, waft it). If it smells sweet, you're burning coolant.

Took it into a place that does general repair and sells decent used tires, so had them look at it. Yup....UIM is leaking. I'm scheduled for tomorrow, $385 after tax. I sure wish I had a garage and a full day that was free...I could do the work, but I have neither. Anyhow, that's what it was. And yup, that definitely explains my drop in fuel economy. QUESTION: This particular mechanic (whom I have not used before but was able to talk intelligently with) is NOT planning on doing an oil change, when I've heard everywhere that it's imperative to do an oil change during that repair - or is that only if/when you do the LIM?? He insists that after he drains the coolant, there won't be a drop that gets into the oil. Should I insist that he change the oil, or doesn't that need done when doing just the UIM?

Personally I'd recommend changing the oil. If you're really concerned with it, it's better to be safe than sorry. If you have the extra money/time that is.

edit: especially if you're a freak about your car like me and one noise or vibration you feel should not be there makes it so you cant sleep easy until its fixed...

Change the oil. It's cheap insurance.

Also, 1 quart every 5k is nothing to be concerned about....

You should insist that he does the LIM gaskets as well as change the oil.

It is only a few more bolts and if he is an experienced mechanic it shouldn't add much more time on the labor. Also insist on them using the metal (GM or Fel-pro gaskets). Done correctly, you will get a lot more life out of this motor.

As for the oil change.....................push it to be done. Even if they use the cheapest oil, but a good filter. Drive it for another hundred miles and then do your own desired oil change.

And dont put Dexcool back in. Have him use the prestone mixes with any.

Get the oil out ASAP. I just had this happen to me. I'm very lucky to still have a motor. Also, when you get the car back and have some time, you might consider blocking the coolant passages into the UIM. That will make sure that this kind of failure never happens again.

This is all good feedback guys, thanks. I would LOVE for him to do the LIM at the same time, unfortunately funds do not allow it right now. I know what you're saying, he's almost all the way to it anyway, but I just can't right now, which kind of bites.

He isn't using DexCool, which is a bonus, because it will be a complete drain/fill of the coolant, which means the DexCool is going bye-bye, which is a good thing. He uses a mixes-with-any coolant.

I'll have him do an oil change with the cheap oil, and next week I'll have a real oil change done. I just don't want to risk the oil being contaminated with a little bit of coolant, and like Ed said, it's cheap insurance. I can't afford to get 'good' oil put in tomorrow, but cheap fresh oil is a lot better than high quality but contaminated oil for the short term. Alright. That's where I'm at. Thanks again guys.

How much more does he estimate for the LIM gaskets? It can't be much...

Otherwise you gotta have all that torn apart again (x2 the cost), and who knows how much time you have left on them anyway.

Bing wrote:
Otherwise you gotta have all that torn apart again (x2 the cost), and who knows how much time you have left on them anyway.

Yup, I know. I get all that - completely. Problem is, I was strapped for cash while the appointment was made. It just so happens, that I got approved for a $1K loan this afternoon, late...as the shop was getting ready to close...and I won't know until morning if he already buttoned up the upper manifold. SO....I will call first thing in the morning, and if he didn't already put the upper manifold back together, I'll tell him to do the lower, too. It was a timing thing. I was applying for the loan 'after' the car was already in the shop (it needs a few more things - new tires all the way around, brake work, and the infamous intermediate steering shaft serviced).

But, here's the REAL update: So he calls me at about 4:30pm today, telling me that the plenum doesn't have the little pinhole (or larger) by the EGR that he thought it did (GRRRR!!!!! So how was he so sure it was 'that' then, to begin with?!). So he asks me if I want to proceed with the new UIM kit. I tell him, yes, go ahead, may as well, you're already there, rather than putting the old one back on. But then, WHERE is the coolant going to?! He did say that the throttle body gasket looked pretty bad, and will be replaced, but outside of that, he said he'll have to do a pressure test to really find out. And of course, my worry is, with a pressure test - if there are any weaknesses in the LIM gaskets that haven't popped yet, a pressure test may make them pop.

I know it's a bit convoluted, but anyone have any 'wishes' that I should pass along to the mechanic? Other places to look, for the leak? Pressure test, or NO pressure test?! Do I have him tear down the UIM again (and pay that double labor charge + new gaskets again probably) if he happened to put it back together already (I'm hoping he hasn't!). Hm.....what to do? I have a little extra cash flow now (although I desperately need tires, and that's easily $500 of my $1K right there, IF I get cheap tires). Suggestions?