Hi all. I have been driving this car non-stop on Los Angeles roads since the engine/trans install a couple months ago. I am running a 160 thermostat and the car has been running super-cool in all SoCal Summer conditions, uphill, heavy traffic, etc. Friday it suddenly began to run rough and the temp gauge showed hot. I am running Edelbrock RPM heads and dont want to risk any problems so I pulled into a service station and waited for it to cool down. I started the car and topped off the water. After a few minutes of driving in traffic the temp gauge showed hot again. I took my time and limped over to my mechanic while keeping my eye on the gauge. He did a block check which came out clean for oil in the coolant. Even with the thermostat removed the car behaved the same. My guy says the block check is 98 percent accurate to detect a failed head gasket but I fear I may be in the 2 percent. I left the car there over the July 4th weekend (ouch). He will test the cooling system further tommorrow. I had my radiator rodded out and working well when he did the engine swap. If it's needed, what's involved in head gasket replacement on this rig? Here is another thread on jalopyjournal that describes my car. Thanks in advance and have a great day. http://www.jalopyjournal.com/forum/showthread.php?t=563772&page=2
in my experience, a block check can be misleading. i've had a few come thru my shop which would p*** the block check at idle, sitting in the shop. sometimes, the leak will only manifest under load. kinda hard to test on a vehicle while you're driving. even worse trying to open a hot cooling system to run a check. as stated above... check the timing. also make darn sure the coolant temp sender is in spec. white vapor coming from the tail pipe ***ociated with a 'sweet' smell is a pretty sure indicator. if you're losing coolant but not 'boiling out' (steam coming from under hood) you might be a victim. lots of small bubbles in the cooling system (like carbonation in a soda) is a possible indicator. make sure there's no coolant in your oil (looks like chocolate milkshake on your dipstick). head gasket replacement is a rather straight forward operation. the trick is figuring WHICH gasket is leaking. dual exhaust is your friend if you have a visible vapor trail. then you can nail it down to a specific bank. if one is leaking it usually makes sense to just do both for safety sake. the heads should be sent out to check for a true deck surface. over heating can warp a set of heads and they may never seal right after the fact.
I had a leak at the valve guide. I pulled the plugs and cranked the engine over. Water spurted out of the offending hole.
It is possible you blew a HG, but not likely. They don't typically just blow, you have to have done something to cause it. Warped or improperly torqued head, lots of boost or nitrous, MAJOR overheat. I blew one on a 302 Ford on a hit of nitrous, but blew it between 2 cylinders, not into a water jacket, so the traditional tests wouldn't work. I knew it was blown by the feel of the engine, and it turns out I was right when I pulled the head. Look for coolant in your oil first, not vice-versa. A compression check on the cylinders can also tell you if the HG is blown. Also, have the mechainc check around your intake manifold for leaks. A manifold leak can behave similar to a blown HG. HG swaps are more labor than anything. Not a big deal. But, if you discover it is a blown HG, GET YOUR HEADS CHECKED!! Make sure they're not warped or cracked, or you'll be doing this again in short order. A little OT, but lose that 160* thermostat, your engine will run much better at 180* and last longer. You're most likely not atomizing and burning fuel correctly at the lower temps, so mileage and power will suffer. The engine will still tend to run where it wants to temperature wise with an efficient cooling system. I run a 180* stat in my 55, with an Edelbrock water pump and aluminum radiator with a Danchuk shroud, but the engine hangs around 170 while cruising, creeps to about 180 in traffic. Even that's a little on the cool side. Make sure you at least have a functioning PCV system, since condensation will become an issue at prolonged low engine temps.
yeah i think i would at least go with a 180,if not a 190 thermostat. jmo.you said it was running rough,if not for that i would say change temp gauge first. good luck with this and keep us posted. these kind of things can drive you crazy
Thanks folks. My guy shot the engine, intake, radiator, etc with an temp gun and it was hot. The gauge works. I believe I shut it down in short order..hope the heads are not warped...will see.
OK...here's the update. The radiator was removed and rodded out but the radiator shop said it had been fine. My mechanic replaced the fan with one that is larger with steeper pitch & more blades, also re-spaced the fan towards the rear of the shroud as it was pretty close to the radiator. I am running the car with no thermostat and it is staying cool. The plan is to run this way for a couple weeks and keep an eye on the temperature. Hopefully the head gasket is good. thanks for all your help folks!
Been running the car in Los Angeles Summer heat for 3 - 4 weeks and it's staying cool in traffic, etc. Thanks for all your replies and have a great day!
Good deal man! I've run cars without the 'stat in summer and never had a problem. I had this 352 Ford that I did this on every year like clock work. Bob
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