The radiator on my 86 was gunky, but the engine ran 185o until the gauge quit working, the other day. I flushed the engine twice. The second time I drove 10 miles before draining flush. I drained rad and refilled the rad with plain water, and filled the block through a small hose on right side of motor. I did not tighten the rad cap. I drove 3-4 miles, and rad lost very little water. I tightened the cap, and drove about 10 miles and my temp guage (which quit working, remember) went to 297o! I drove home, and car "rattled" when I accelerated. I hope I did not fry my motor! When my hubby opened the petcock about a cup of water came out. My question is what happened? Anybody have any idea - given the circumstances I described? Before I flushed it it had no antifreeze in it, and it still ran 185o. Could my thermostat be suddenly bad? I am 99% sure the rad was full of water when I filled it. It was running out in both fill spots - rad and small hose going to intake manifold. Thanks for any advice & help. My mechanic is out of town for a while. One more question: Should I use 160o thermostat? I see in another thread it is (mostly) recommended.

 

Could somebody at least answer my question abouty the 160o thermostat?

 

When you filled your cooling system did you burp it to eliminate air pockets? Pull your thermostat and see if it's in backwards or stuck. Try running without it.

Are you telling us you drove your car and now it has NO WATER in it? Any evidence it leaked out while driving? Did you have smoke coming out your exhaust? If this is the case it may be very bad news. All the coolant gone and no evidence of a leak is a bad head gasket or a cracked head.

170 thermostat should be fine btw.

 

As previously stated, I drove it 3-4 miles with the rad cap untightened. The rad was full. It was only after I tightened the rad cap that I had problems How do you burp a rad? Anything like burping a baby?

 

Fill the radiator. Then fill the overflow tank to the half way mark. Start your car with the cap off. Turn your defroster on so you circulate through your heater core as well. When the thermostat opens you should see your coolant drop. Run your engine at 2000 RPM add coolant to the top and cap your radiator. Drive it around for awhile. Carefully remove your cap see if coolant has dropped again add as needed. You can also drill a .125 hole in your thermostat to allow air to pass.

 

What about filling the block? My mechanic suggested I remove the 5/16" (?) rubber hose that goes to the heads, and pour water into the head through this rubber hose using a small funnel. He didn't mention the heater. I think that is an excellent idea. Thanks.

 

Above is the correct way to burp a system, but let me add a few things.. It helps if you raise the front of the car a foot or so off the ground, the radiator on a Corvette is lower then the motor so raising the front helps get the air out....It may take 2 or 3 times of burpiing for the cooling system to get rid of the trapped air.. If you do like "Lonestar" mentioned above and drill 1 or 2 small holes in the rim of the thermostat this will help it burp itself and make the job alot easier..I usually put 2 x 1/8" holes in my 180 degree thermostat and this works fine.....WW

 

WW7 nice tip on raising the front of a vette. Noted and added to coolant change procedures.

 

I'm starting to wonder about your mechanic. I have never filled the block or even heard of doing that. If you follow that procedure i gave you it should work. Be SURE your thermostat is facing the right direction.

 

Thermostat info:http://temp.corvetteforum.net/c4/vader86/

 

My mechanic says he fills the block to eliminate trapped air. Maybe it is quicker than the other way of doing it. I notice that the Superstant 160o thermostat has a notch cut in it, that basically does the same thing you are doing by drilling holes. By drilling holes aren't you defeating the 180o feature of the stat? It seems that way to me, but I'm just a dumb broad. Nobody has answered me whether using a 160o stat is a good idea. I hear it is a REAL GOOD idea in the summer time!

 

It depends on where you live. Warmer climate a cooler thermostat. A 170 is a good all around number to use. As for the holes you will not defeat your thermostat as they are very small and won't affect temperature but will release air.

 

If everything is working correctly, a factory stat should be fine. If you stayed at 185 before, just fix the current problem and no reason to change stats (IMO).

 

I see no reason for a 160 stat. 185 is about right. The burping procedures and hole drilling are tried and true methods. The holes will not allow enough water to bypass to make a difference in cooling, but will allow enough air through to not create a bubble. Revving the engine while filling the rad is called "packing" the radiator. If you apply all of these methods, and your fans are working properly, and your air deflector dam below the car is not busted up, and your radiator is clean inside and out, you will not overheat. If your radiator is "gunked up".....non of this will work.

 

I think after 2 flushings, including an unfortunate steam bath, the rad is clean. Is there any reason NOT to use a 160o? I really want to try it because I hear it's good for Fla. in summer. They said further, that even though it was a 160o, the engine ran 180o. I read that here on this forum, I believe. Of course for EVERY plan there is a naysayer, or 2. I guess that is human nature. Anyway, guys, thanks for all the help. My mechanic has a set of portable ramps. I will ask him to use them on my car, when he re-fills the rad.

 

It won't hurt using a 160 degree stat in Florida, but the only thing a 160 will do is it will open up earlier. Once the stat opens at 160 degrees the temperture of the motor will continue going up until it hits its "true running temperture", which should be somewhere around 185-195 degrees with a stock cooling setup . From that point on its up to the fans , your car speed, and the ambient temperture as to where your engine temperture will be...So using a 160 or a 180 makes no difference in the end result during hot weather, .....The car will end up running above that temperture anyway..The only way to lower your actual running temp is to make changes like a larger capacity radiator like a Dewitt's, resetting your fans to come on earlier, or some other changes that would allow a better air flow through the radiator.....Just putting in a lower temp thermostat will not change your actual running temperture...These are proven facts I am quoting , not unproven theory.... . Hope this answers your question..........WW

 

If you drove it wiht the cap off once the thermostat opened you puked most the water out thats all.

 

Have someone with an infra red temp gun take measurements across your radiator, and look for cold spots. It should be within 10-20 degrees of the upper radiator hose temp. This will tell you if your radiator is cooling correctly. You had a previous thread going, where I suggested an alternative method of unclogging your radiator that has worked for me on several occasions where multiple flushes did not work. Any temperature working thermostat will work (including none) if everything else is up to snuff.

 

QUOTE=cuisinartvette;1583342226]If you drove it wiht the cap off once the thermostat opened you puked most the water out thats all.[/QUOTE]

 

Well stated!!!