Engine blowup [Archive] - SaabCentral Forums

: Engine blowup

Eric van Spelde
5th May 2002, 02:57 PM
Engine: 2,500 kms 'old' 2.1 litre bored & balanced bottom end. Rebuilt '87 B202 cyl. head.

Symptoms: all of a sudden, clouds of blue smoke from tailpipe on full-boost accelaration. Looked under bonnet: throws out oil through the filler tube. Lost close to 1 quart of oil within 60 miles, and also a fair bit of coolant. White 'mayonaise' stuff in the top part of the dipstick tube, so coolant is mixing with engine oil. Traces of oil leaking onto turbo heat shield. Both crankcase breather hoses look OK, aerospace grade check valve fitted in smaller of the two lines

Seemed to run OK otherwise on limping home, but idled a bit lower than usual and sounds just ever so slightly different than usual, indicating that it might not have even compression on all four cyls. Had to move the car today and it barely idled at all. Idled perfectly smooth and went like sh*t off a shiny shovel before this happened. Did use a fair bit of oil, though, and there were some whezing sounds at certain rpm's/loads,and some tapping noises on idle.

Methinks the headgasket has blown and oil is leaking into one or more cylinders when under boost. But would that alone cause such enormous crankcase pressure? And what would cause a professionally installed head gasket to fail in under 2,000 miles, given that I'm running fairly moderate boost now (although before, APC would allow 'beyond red' boost.)

I'm baffled and frustrated.

Any help?


5th May 2002, 09:46 PM
well u definetely are having problems sealing the compression for each cylinder, did u use new head bolts for the head job or not....When the head gasket is blown it allows compression into the coolant system which will build up enough pressure to blow one of the weakest hoses in your system and also allow pressure to get into the oil system which causes the "mayo" that is coolant mixed with and compressed with oil now about the oil spraying out of the fill tube over full oil level or enough coolant in the oil pan that it moves the oil up re:oil floats on water..and therefore ruins your mains!!!!( not a good thing at all!) well that should answer that feel free to ask anything else

5th May 2002, 09:50 PM
oh sorry the oil on the turbo shield is caused either by an increase in oil pressure hence it leaks at the weakest spot,and or there is an o-ring in the dist that keeps oil in and its not doing its job so replace it mine i had to cut off w/ a knife it was rock hard.

Janne Selinummi
6th May 2002, 04:57 PM
Oh dear!

I really hope it's nothing but a blown head gasket. Eric, all good wishes for you and your lovely car!

6th May 2002, 05:03 PM
Have you checked the check valve isn't gunged up with oil. The Norgren valve used by Trent is smaller than the standard Saab unit.

12th May 2002, 08:10 PM
Could it be blowpast on a broken piston ring?