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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 87 K20 on May 01, 2011, 07:18:24 pm

Title: 87 350 coolant loss/ bluish white smoke
Post by: 87 K20 on May 01, 2011, 07:18:24 pm

hi all...I have an 87 K20 with a 350.  Just recently I noticed the driver's side tail pipe was blowing bluish white smoke, even after it was at operating temp...Oil level is fine, so I know its not burning oil, but it is going through coolant pretty quickly.  I took it to a local shop to have a pressure test done, and they said everything checked out fine except for a small leak at the thermostat housing....the smoking has gotten worse, but it doesn't do it all the time...it does it sporadically.  Anybody got any ideas about what could be causing this problem?

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: Grim 82 on May 01, 2011, 08:03:10 pm

Sounds like a blown gasket, probably head or possibly the intake. Coolant is getting into the cylinders if you have white smoke and coolant loss.

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: bobcooter on May 01, 2011, 08:07:42 pm

x2 what Grim said. It could be a head gasket or the intake gasket. Park it on cement or slide a piece of cardboard under and make sure there are no leaks any where on the outside too. If you find a leak and it is still smoking, check your transmission modulator valve for a pinhole in the diaphraqm. It could be sucking trans fluid into your intake and causing the smoke.

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: 87 K20 on May 02, 2011, 09:46:08 pm

Thanks for the info guys...i just dropped it off at the shop tonight to see if they can diagnose exactly what's wrong...I don't want to do a ton of work to find out I didn't fix the problem.

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: beastie_3 on May 02, 2011, 09:55:39 pm

ya but doing it yourself is free

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: bobcooter on May 03, 2011, 03:26:55 pm

Beastie's right. I usually have more time than money and working on these things is half the fun of owning one.

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: beastie_3 on May 03, 2011, 03:55:44 pm

plus you learn something about your truck, and if you do have to take it in the shop, you will be less likely to be scammed

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: bobcooter on May 04, 2011, 03:01:42 pm

Great point Beastie.

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: big bear on May 04, 2011, 05:40:53 pm

i fully agree guys

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: fitz on May 04, 2011, 05:57:46 pm

How many miles are on the motor?.
I fully agree with Beastie, but if you are paying someone to replace your headgaskets/heads you may want to think about putting in a new or rebuilt motor. You will probably already be spending half the amount of money anyway on the headgasket job.

Title: Re: 87 350 coolant loss/ bluish white smoke
Post by: 87 K20 on May 21, 2011, 06:30:58 pm

Thanks for the comments guys...i actually am in the middle of replacing both head gaskets myself...I just took it to the shop to make sure I was fixing the right thing...I am definitely learning a lot!