I have a question for anybody out there, I have a problem with cooling just after startup. The engine warms up rather quickly and the temp gage pegs at 250 for about 10-15 seconds and then returns to normal, (190-195). Now I know the gage is correct, because I installed a screw-in gage and it verified that the dash gage was correct. I installed a new 180 thermostat and a new radiator cap. I am running Pro-comp aluminum heads, high volume water pump, new radiator with electric fan. I had a 160 stat in it and the temp was all over the place. Cruising down the road it would peg the gage and then return to normal for a while and then repeat it again then entire time I was out. Any suggestions. Thanks
I really can't tell, the hose is braided and doesn't squeeze that easy. But the stat is brand new, I know that means nothing because it could be bad. I had this same problem with a 160 stat which I found to be opening at the boiling point and then when removed from the water it closed very slowly, thats why I put a new 180 in it. Now after I put the new stat in I took it for a ride and it ran 190-195 and sat there for the entire ride, approx 10-15 miles with no problem. Since I put the 180 stat in, the first time I started it was the only time it went high temp and then returned to normal and stayed there without cycling to high temp and back. I am just afraid of damaging the heads from the extreme heat until the stat opens if it continues to do this.
Would it help to drill holes in the stat to help keep the coolant flowing until the stat opens. I know this is a long reply, but I am trying to give all the info I can remember as it happened. Thanks
I would take out the thermostat completely and see what happens with it out... if it stays cool then the thermo is of course bad.... i use to never run thermo stats in my old trucks, it only was a bummer in the winter time when it took a while for the motor to warm up.
Drill a 1/8th inch hole in the solid part of the thermostat and position it at 12 o clock in the manifold. This will let air on the high side migrate out of the intake and let enough coolant flow to lower your peak temp before the
stat opens.
good luck,
some stat companies incorporate a little jiggle valve on their stats that do the same thing.
T-4-2, pull off your radiator cap, crank your engine up, grab a flashlight and get comfortable......looking down into the radiator at your your coolant.....you'll see it start to smoke.......keep looking, and then you should see water slowly start to flow by, (starting to open).......after a few seconds....it should really speed up (Thermo all the way open).
You shouldn't have it peak out and then open unless you got some air anyway. Sometimes this is hard to get around. On countless occassions....some engines you just gotta take the thermo housing off and fill there slowly, then put your housing on and fill some more. If you got heater hoses anywhere.....it don't hurt to leave one loose....just remember to tighten it after filling. Then you gotta make sure your water level is over your inner cooling tubes in the radiator at least.Some folks have problems with the upper radiator hose too high. If thats the case.............
Summit Racing has this little piece with a radiator cap you can put into your upper radiator hose.........
If it gets Really hot really quick....your probably getting combustion chamber gas into the coolant somehow.....probably a seeping gasket on the head somewhere.
Hey....just because something is new....that don't mean its OK. Doublecheck things.......I've even seen the waterpump impellars com off...........
Keep us informed and let us know what you find.....
Ok, I tried drilling the thermostat and that did not work, still jumped up to approx 240. I removed the thermostat and replaced it with a large washer with about a 1/2'' hole in the center. refilled the system, started the car and let it idle for about 10 minutes before it reached 200. I then got in and drove it for a few miles and it cooled down to about 180 and stayed there. Now, I only drove it for about 3 miles but it never got above 200. I will have to take it out for a long run and see what happens. Now it hit 250 several times in the past but only for approx 10-15 seconds before it cooled down to around 180. I sure hope I did not damage anything, like maybe a head gasket. I will keep you posted on what happens next. Thanks to all for the great suggestions.
You may want to check the ground on-to your gauge... ?? and I would leave the washer out all together, I have not run one in mine for many years.. But you do what you have to do to get correct head temp, that is the main problem with Alum, heads... just a thought..
I will check the ground and remove the washer, drive it for awhile and see what happens. I know the gauge is pretty close because I bought a screw-in gauge and put it in the head and it did about the same thing. Like I said after I put the washer in the stat housing it did not peg the gauge and seemed to stay cooler. I will remove the washer and let you know what happens, tomorrow. Thanks to all again for the good ideas.
Yea....you need to check Teds scenaro.....I've heard of that happening.....(PSssssst- Thats why Teds a Master Craftsman......He's forgot more than most peopke have learned in a lifetime!) It could be and probably is a electrical fault. Need to check it agianst a good mechanical guage would be the next step after checking for ground problems.
If it pegs out for just a few seconds......I wouldn't worry about anything being hurt. Anybe.....but I wouldn't think so. BUT.....if you've got the tools.....do a pressure leakdown test of your cooling system.......if you got aluminum heads.....I have seen them get porosity in places where it would heat up quick........keep us informed!:lol:
Hey T-4-2, I would suspect you got a gas problem. Even when you do all the right things to de aerate the system it goes back and behaves like it has air.
Leak that baby down. Use as much pressure as your tester will allow, leave the radiator cap off, and leave the pressure on each cylinder for a couple minutes while you check the coolant for the dreaded bubbles.
Ok all, I removed the washer, refilled the radiator, changed the oil and filter because it was black. I am assumung it was from being hot and breaking down. I started the engine and let it run for a few minutes and it barely got to about 160. I drove it around for a little while and it never broke 185. So far the no thermostat idea is working. I believe this might be the fix for the problem. I will drive it some more Sunday and I hope this is the last time I have to worry about the cooling.
I want to thank everyone for all the suggestions and hope this is the last problem for quite some time.
Hey T-4-2........if it drives fine and no more problems........hey.......there's a lot to be said for....... 'If it ain't broke.....don't fix it!'.........
I drove around and the temp stayed right around 180, with the ambient around 85. It appears to be doing just fine, thanks for asking, and again thanks to all for the help.
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