coolant leak & running hot

[pmcgrath]

Just recently installed GN1 heads, ported intake, MSD 50s and ATR 214/208 cam and not long after my car started running hot. Once the temperature started to rise, it kept rising well over 200 deg. I pulled out the 160 thermostat I only had in the car about 2 months and stuck in another one. That seemed to do the trick for a while. Now when the car warms up, it keeps warming up to well over 200 deg. once again and now there is coolant leaking from somewhere on the passenger side of the motor. Could the tstat be sticking again? What would be causing this? The coolant is dripping from the shield near the starter but I can't see where it's originating from. I can hearing a hissing/gurgling noise from the passenger side when it's warmed up too. Any ideas on where to start looking at these problems would be appreciated !!! I'm going to fire it up again tonight and put it up on jackstands to see what's going on.

Thanks,
Paul.

 

[TurboDave]

Originally posted by pmcgrath
Just recently installed GN1 heads, ported intake, MSD 50s and ATR 214/208 cam and not long after my car started running hot. Once the temperature started to rise, it kept rising well over 200 deg. I pulled out the 160 thermostat I only had in the car about 2 months and stuck in another one. That seemed to do the trick for a while. Now when the car warms up, it keeps warming up to well over 200 deg. once again and now there is coolant leaking from somewhere on the passenger side of the motor. Could the tstat be sticking again? What would be causing this? The coolant is dripping from the shield near the starter but I can't see where it's originating from. I can hearing a hissing/gurgling noise from the passenger side when it's warmed up too. Any ideas on where to start looking at these problems would be appreciated !!! I'm going to fire it up again tonight and put it up on jackstands to see what's going on.

Thanks,
Paul.

Well, sounds like one of the head bolts are probably leaking coolant past the threads. The first "hot" run could have weakened whatever sealant was there. But sure sounds like head bolt, and/or head gasket leak.

You'll also need to figure out what's causing it to run hot. Let the car sit and idle while you watch for coolant fan operation. Does it come on at all??

 

[pmcgrath]

Thanks for the tips Dave. When it first occurred, a couple of days ago, I thought maybe the passenger side head bolts may have come loose as well. So I retorqued those. The bottom bolt closest to the firewall (my favorite) needed 1/4 to 1/2 turn to be tightened. I thought this was it. Anyway, fast forward to tonight, I took the cap off the rad and discovered that it was quite low on fluid. I assumed that it was full as the overflow tank always looked ok ... oops. I then emptied the overflow tank and discovered alot of gunk at the bottom (just started using RMI-25). I cleaned out the overflow tank, topped up the rad and fired it up. Temps are now normal, but what is more bizarre, is there was no leaking. Any idea why it wouldn't leak running at 165 deg vs 225+ deg. Not that I'm complaining ... just wondering why.

Thanks again,
Paul.

 

[azgn]

if your overflow tank was full, you were pushing water back thru the block (bad seal at the gasket)......you don't lose any, it just all winds up in the overflow

if I were you I would retorque everything and put some GN sealant tabs in

 

[TurboDave]

YES!!!! Get some GM sealant tabs. They will cure any minor pesky leaks that you can't find, and seem to only show up at extreme high temps

 

[pmcgrath]

Will do first thing on Monday. Thanks for the tips !!!

Paul.