Pushing Coolant into tank

[buickboy]

New motor (<1000 miles) 2 Steel shim headgaskets. Motor is not getting hot ever, but it is pushing coolant into the recovery tank to about half full after a 20 lb boost run. It is not blowing it into the tank, just pushing it. Now, the radiator will not suck coolant back into the radiator from the tank. What is going on? Anybody with this particular experience? Car runs real good (7.1 in the 1/8 @ 20 lbs boost). Arp head bolts, all the usual goodies.
Please email to: mitch.smith@lmco.com with comments/suggestions
thanks,
Mitch

 

[OldGrayII]

Did you retorque the heads! The heads are probably lifting, but the shouldn't be at only 20 lbs.! Thats rather strange, maybe cracked head!!

 

[buickboy]

Come on guys. I know i am not the only one in history that has this problem. All experiences welcome
Mitch

 

[TurboDave]

Well, not working from experience, but from advice and hearsay; with steel shim headgaskets (expecially two), unless they're done perfectly correct, you'll get the same symptoms as a blown headgasket (pushing cylinder pressure into the cooling system), etc.

 

[Steve Wood]

My preference is steel shims...but only one per side. What did you use for sealant? Clear silicone works very well. Some have reported problems with the copper sealer over the years.

The heads and decks have to be perfect when using shims.

You can try having the coolant tested for exhaust contamination.

 

[buickboy]

Fair enough Steve. I installed the shims at with the advice of a very good engine builder with alot of experience. I had the heads milled and the block carefully checked by a very good TR machine shop. I installed the shims with spray Hylomar on both sides of each shim and torqued heads with arp bolts to 75 in 3 steps. Retorqued next day, and checked torque after four heat cycles. Used PST sealer on the bolts. I repeat the car does not get over 180 on a run and cools right back down to 168 in 91 deg ambient. Runs like a striped Ape and idles great for a 112/112 cam. Does not fill the recovery tank in normal driving.
Mitch

 

[StagedGN]

simply put the steel shims not worth the trouble! get a good quality head gasket and be done with it.as previously mentioned same problems as having blown head gaskets.Do Not run the motor anymore in this condition.

 

[azgn]

same problem.......re-torque the heads again (loosen the bolts and re-torque) put the GM sealant tabs in.....no probs since (I was pushing coolant at 21 psi) this was with ARP studs

 

[Steve Wood]

Assuming the radiator cap is up to snuff...give the sealant tabs a try. As I have never run double shims, I cannot attest to how good or bad it works. Single shims are the best gasket out there in my opinion altho one is more likely to blow something out the bottom than lose a gasket.

 

[NCTTA]

I had the exact same problem only with oringed heads and 1007 HG...resurfaced the heads and studded them....no problem now. When I pulled the heads you could see plain as day the compression path into the water jackets.

 

[OldGrayII]

Buickboy, as I told you up top, ReTorque the heads!! Then you "SHOULD" be O.K.

 

[Quick89]

Pushing coolant

I had the exact same problem with the stacked steel gaskets at 20 lbs. of boost, re-torqued the head bolts and the problem was fixed

 

[buickboy]

Consensus is to retorque head bolts. I intend to do just that, but have a few questions first. 1. When loosening head bolts, should i remove bolts one at a time and apply more sealer to threads. I used PST when motor was built. 2. Is it benificial to loosen the intake bolts before retorque so as not to be in a bind. 3. removing headers make it easier to get to the bolts and get an accurate torque? 4. Should i go up to 80 ft lbs at retorque?
thanks guys
Mitch