My car overheated twice in the past 2 weeks, and the last time was enough to keep me from running it anymore. I also was having rough idle, coolant loss with no visible leaks, and a misfire code on #7.

Last night, I got the driver's side head off and it is very apparent the coolant was going into #7.

In trying to determine what caused this, I noticed the steam tube is completely clogged where it meets the driver's head. The passenger's side is still flowing though.

Question is, could that port being clogged cause the head gasket to blow at #7, or cause the head to warp enough to create this problem? I would hate to get it all back together and not have determined the cause of the problem.

Thanks,
Thomas.

 

I'm glad you posted this question. I had a mysterious coolant loss too that has since stopped. The engine idles a little rough and there's an intermittent miss that is not throwing a code yet.

I know the steam piping on the LS1 is to let air escape from the heads and figure it is the same process for the LT1. Car Craft had an excellent article about the LT1 reverse cooling and how hot spots can occur in the heads. What you suspect about warping makes good sense. I can't answer your question but with the blockage it wouldn't be hard to imagine a hot spot, boiling coolant with no escape route and warping. Which brings up the need to have the head checked for flatness.

 

Ya, agreed. It's my understanding the steam pipe allows any trapped air in the heads to flow back to the radiator where it is supposed to be seperated from the coolant. I guess that means air could have been trapped in the back of the head, right at #7, and caused this to occur.

I'm having the heads checked for flatness/cracks, and assuming I can reuse them, will be doing a valve job plus some mild porting on the heads and intake.

I'm not willing to do a cam with 140k on the clock, but with the 1.7rr and headers, I figure why not do a bit of work to heads while they are off.

Thomas.