Advice-replaced all gaskets - still white smoke from exhaust



I’ve been working on my 199 buick lesabre custom 3800 w/ 160K for a while now. It was smoking really bad, white smoke, it was clearly burning antifreeze. So a couple weeks ago I did the head gasket, intake manifold gaskets, exhaust manifold gaskets, etc. A month or so prior I did the upper intake plenum gasket and throttle body gasket.

What was weird, is that the head and intake gaskets looked fine, and since the smoke started back by the exhuast manifold where it connects to the exhaust system, we replaced the ring as well that goes in there. The left valve cover was gross, with orange (coolant?) crust around it. It no longer smokes around the engine, but two days in a row it will smoke on start pure white (no oil burning -smells like coolant) and disapate in 1 minute or so, but apparently continues to burn, as my coolant reservoir needed refilling after 30 minutes of stop/go driving around town.

Since the car was run only 5 to 10 minutes after installing new intake plenum and throttle body gaskets (throttle body did look bad, and plenum showed signs of burning a little) I did not replace those.

Is this something with my valves? I would associate the valves with oil burning…

I’m at a loss here and almost ready to buy a different car.

thanks so much


Did you have the heads checked for cracks before you installed them?


Sadly, no. But I never overheated the car, and I inspected them for cracks and checked surface levels with feeler gagues, and all checked out as far as I could tell. I shined the heads up super nice. All that said though, I suppose there could be a crack. I personally don’t believe there are.


Even though it looks like there are no cracks you might not be able to see them with the naked eye. I always have the heads checked by a machine shop to be certain there aren’t any cracks.

Hopefully this isn’t the case,it could be leaking coolant somewhere else.

Have you triied pressure testing the cooling system to see if there is a leak? With a pressure tester you could pressurize the system and see if it leaks down.

If it leaks down then I would do a cylinder leakage test. Get a cylinder on TDC, apply air pressure and see if there are air bubbles in the radiator. Air bubbles would indicate that you either installed a head gasket wrong or a head is cracked.


I have not tried pressure testing the cooling system. I can probably do some research, but I’m assuming this is something a garage would be better equipped to handle.


While I’m thinking of it, I did have to guess more or less when tightening the bolts on the intake manifold gasket. That’s really the only area I had to guess on when reassembling the vehicle. So naturally I’m inclined to blame myself, but I suppose there are other issues I didn’t consider (like the leak down test).

Thanks for the advice so far.


[b]The only thing I have to ask is, did also replace the plastic upper intake manifold itself? If not, that’s where your problem lays.

If you look at the area of the upper intake manifold where the EGR gasses pass through, you’ll find that the plastic has been eaten away from this area from the EGR gasses. Once this happens to these upper intake manifolds, they can’t be reused because you’ll never get the new gasket to seal.

So, if you didn’t replace the upper intake manifold, that’s why she’s still leaking coolant.



I have the old plastic plenum, not the series 2 that has the egr problem.
I was thinking about tearing that back down to see if I could tell if things were still leaking, but I’ve already replaced all those gaskets.

It’s possible, but when I took it off the first time prior to doing my other engine work nothing looked abnormal.


Hi I have a 1994 Lesabre and it had the white smoke from exhaust coming home from vacation. We stopped at the nearest garage and We had the Vacuum Modulator replaced.Sure enough fixed it no more white smoke.
Replace the Vacuum Modulater


spend the 30 and buy a torque wrench. that would eliminate mucho mucho problemo, neccictan mucho mucho trabajan


I think that billnmd2006 is correct. We had similar symptoms on our 1990 Lexus LS400. One additional clue we had was that we were losing power steering fluid. Apparently this valve provided a pathway between the steering fluid and the head. On start up we would get anywhere from a light puff of white smoke to a substantial cloud of white smoke… then it would clear up.


Some service manuals call for re-torquing the cylinder head after the car is run so many miles. Does your service/repair manual require this? The manual, also, shows the sequence and torque steps to follow in torquing the head bolts. Did you see it?