Blue Smoke & Lots Of It!!!!

cudaz101

Registered User
I was airing out my 90SC 5spd., it had been sitting for about two weeks without starting it...I had to move it oput of the way, so instead of just moving it and shutting it down I took it up the road to dry out the exh and warm it up a lil bit...Well at the end of the drive I took it through the gears to rev it out a lil and in thrid I hit 5K and heard a lil poof "AIR" sound under the hood and then loads of BLUE smoke out the tail pipes...

I slow down get it to the side of the road and pop the hood...

Well the aftermarket oil cap "Rubber detent seal" blew off and there was a pretty good puff of air coming out of the vlv cover...

There seems to be not other noises or misbehaviors...I was thinking PCV Valve, but it it quite a bit of air...


What do you guys think is going on?

thanks

Brad
 
you may have more crankcase pressure under boost if car is cold until pistons warm up and tighten the seal these cars have forged real loose fitting pistons till they warm up and expand more than others i try not to do that its probably hard on parts till they get warmed up sounds like it may be to late hopefully you just blew pcv valve out or something mine will smoke noticeable barely noticeable in the mirror if i rip on it cold
 
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OK....

First...The car was not cold, it was running at normal temp when I aired it out on the way back from the drive...It was fine until the top of third gear, that is when it blew the oil fill cap off and blew smoke out the tail pipes...

I am gonna look at my PCV system...I think I may have lost a piston/ring...But I have no harsh noises metal to metal or knocking...I am gonna do a compression test on the passenger side...I will know soon enough I guess...

Anyone else that recognizes this scenario with one of there own in the past please reply...I would like all the information possible..

Brad
 
Hey rlong, check your information! These cars do not have "forged real loose fitting pistons", the stock pistons are cast hypereutectic aluminum alloy designed specifically for a tight fit and less expansion. There should be no cold knock.
 
Do a compression check first. You might have a leak in the intake manifold between the head. It will suck in oil when in vacuum and blow air into the crankcase during boost. Mine bellowed blue smoke when the headgasket went. So did our forklift.

When I did the compression check on the SC the #2 cylinder had 220 psi the rest were about 150. The forklift didn’t even show a difference between cylinders.

Jeff


Forged Pistons, I wish.
 
Sounds like...

A cracked piston, or ring...Headgaskets!!

They may not necessarily make any noise , especially if it is a cracked piston. I had this happen on my 65 Mustang with a 289. Car sat for 2 months while I was in bootcamp. Came back, started up, ran great till I went to get some gas, and on the way back, BAM, started running like crap, lots of blueish smoke out pipes. I broke a ring, and was losing compression bigtime.

I seriously doubt the problem is as simple as the PCV valve, especially with the amount of pressure in the crank case that you described.

An educated guess would be headgaskets (most likely), or the previously mentioned cracked piston (less likely).

Check your coolant for oil residue, and oil for coolant. Try not to run the engine any more than needed, coolant in the oil will ruin the rotating assembly (bearings), requiring the entire engine be rebuilt.

Good luck

Phil
 
News...

I am tearing my 90SC down, have yet to do a compression test, have no antifreeze in the oil or vise versa, but regardless if it is a lower intake gasket or the HG's I gotta tear it down to nothin' anyway...Then will do the compression test...If i find some cash real soon I will just do another rebuild and rest easy for a few years knowing it has a fresh rotating assembley...

Thanks for all the thoughts and suggestions....Will keep ya posted on the outcome...

Cheers


Brad
 
Verdict IS....

When I did the compression test it failed @ "ZERO" on one cyl. and was @ 150-180 on all the others and that is with 105K on it...I was surprised that all the others were as high as they were with only the one bad one...So that all spells rebuild for me, and I have barely even finished the break-in on my 94SC rebuild...Sheesh... :rolleyes: ...This sux pretty bad...


Brad
 
Actually sounds like you did what I did. Probably have cracked ring land or lands. I broke two on mine and it blew oil all over my engine compartment. Pressurized the cranckcase and shot out the dipstick and just covered evrything. I was of course at the track about 3/4 of the way down when it went, I'm sure people hated me. Mine didn't make any noise either, just noticed it nose down a little, due to losing cylinders, but other than that and oil felt or heard nothing different.
 
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