White smoke and rough starts after replacing radiator

ptaylor-01 · Post by **ptaylor-01** » 29 Apr 2011, 20:03

I have a 96 850, non-turbo, that I've been using regularly for a few hundred miles each week for a few years with absolutely no major problems. Recently, the radiator went, so I just replaced it about a week ago. Ever since replacing the radiator, I've had some strange behavior:

-engine runs very rough at a cold start
- white smoke comes from tailpipe, and then completely goes away once engine is warmed up
- low coolant light comes on and off while driving, until engine is warmed up, then never comes back on

I've since once had a check engine light after a rough start, and pulled codes p0302 and p0300 (cylinder misfires). For the sudden rough starts, I'm guessing that I need to recheck all the vacuum lines that I had to disconnect when removing the old radiator, or possibly clean the MAF. A couple of years ago I did fix a similar problem with very rough idling, similar codes, by replacing a broken vacuum line going to one of the devices mounted on the fan shroud to the intake.

What I don't understand, and am a little scared of, is why I suddenly have white smoke blowing out the tailpipe, and the red low coolant warning light coming off and on, and then both problems going away after running the engine until it reaches normal operating temperature.

And again, this car was working perfectly fine before replacing the radiator.

Any ideas would be greatly appreciated. Thanks a lot.

Polvora79 · Post by **Polvora79** » 29 Apr 2011, 20:28

It seems like something is wrong with the new radiator, because of the coolant light going on and off. check for water leaks and the water pump! about the cylinder misfires could be the fuel injectores or the fuel pressure regulator. but as I can understand you have a water leakage going on, don´t run the engine till you find it! what about the coolant level, is it going down? but the leak may be really low, just a few drops, other wise your car would be stocked! any ways check the fuel system it could be something simple, like some unplugged wire. good luck!

ptaylor-01 · Post by **ptaylor-01** » 30 Apr 2011, 13:32

Thanks for the response. So far it would seem that the coolant level is going down slowly, but no sign of any leaks. The strange thing is that once it runs a few minutes, and reaches normal operating temperature with the temp gauge right in the center, the white smoking just stops, and so do the red warning lights for low coolant. I've driven this car over 40 miles, and not once did the temp gauge move higher than normal. I'm just perplexed why the white smoking would just stop after reaching normal temp on the gauge.

ptaylor-01 · Post by **ptaylor-01** » 12 May 2011, 07:26

I have some new information on this situation. I'd driven this car a number of other times, and had to refill the expansion tank about every 100 miles from losing coolant. This weekend I finally had time to do some more extensive testing. What I noticed what that for the first 10 minutes or so, the car would run fine, and there were no leaks. After some more time running at normal operating temperature, I noticed a coolant leak seemingly coming from the expansion tank. I then replaced the expansion tank and cap with brand new from FCP. When retesting, it did seem fine at first, but again after awhile, the same leak seemed to come back. But, after taking a much closer look, it was actually the brand new expansion tank cap releasing pressure, and coolant in the process! Last night, I did compression tests, since I also have been receiving the P0302 code.
Each cylinder came back the same, right around the 150 PSI mark, more or less slightly. HOWEVER, when testing the cylinder number 2, I also discovered that my compression gauge got some liquid on it, which does seem to be coolant. When taking a look into that cylinder with a light, I do see some fluid in there as well.
So, going back to my original problem a month ago with my rupturing radiator, I presume that's when my head gasket went near the second cylinder. When I replaced the radiator with a brand new one, that left the expansion tank cap as the only other weak link to allow the exhaust gases building up in my cooling system to escape, due to the head gasket issue around the second cylinder. The car did come very close to overheating (or maybe did) about a year ago.

Does anyone have a comment on that observation, does this sound about right?

This car has over 240k miles on it. I love it, but it's a 1996. Is it really worth doing the head gasket/rebuild at this stage? On this car I've done the PCV sytem, smog pump, tuneups, axles, brakes, etc...nothing more complex. Is this feasible as a DIY job for a car that I'd really need to work right?

Post by **jblackburn** » 12 May 2011, 07:45

It does sound like a head gasket - just a small leak. The water in the cylinders is what's causing your misfire, though. Honestly, you might be better off looking for a "new", less tired engine if you decide to keep the car - 150 psi is getting on the low side for compression.

gilhuly · Post by **gilhuly** » 12 May 2011, 07:48

It sounds like you are on the right track. It definitely sounds like a head gasket failure. The only other step would be to test the coolant expansion tank for exhaust gasses using a kit from NAPA or wherever. Good luck.

ptaylor-01 · Post by **ptaylor-01** » 01 Aug 2011, 15:10

UPDATE:

I've tried a "radiator stop leak" product from Bar's, and so far it's been buying me time. I put it in about 2 months ago, and so far the problem has disappeared.

Any ideas on how long this stuff lasts? I've driven at least a couple of thousand miles so far.

ptaylor-01 · Post by **ptaylor-01** » 19 Mar 2012, 18:49

UPDATE: I've decided to do the head gasket job. After finally removing the head yesterday, I found signs of coolant in the combustion chambers, so it was definitely time.

Can anybody recommend a good machine shop in the lower Hudson Valley of New York? I'm in the Fishkill/Poughkeepsie area. For anyone who's done this in the past; did you have a Volvo specialist do your valve job/machining, or was it a regular machine shop? Thanks.