engine temp

E

engineer36

Active member
hello, great forum. i have a 65 mustang 200 6 stock, engine seems to run hot, infared temp gauge on on head reads 190 temp gauge in car pegged, reading at radiator 190, reading at themostat housing about the same. i live in central florida very humid, after 30 miles of hard driving shut car off coolant boils over to catch can, after cooling goes back to radiator, no coolant loss, is this normal, what temps should i be running in these conditions, thanks
 
First, backflush the cooling system (inexpensive kits at most parts stores) and get a new radiator cap. Second, put in a "Summer" thermostat, maybe even 160*. Third, move the heater hoses to the opposite side of the head. Fourth, if you have an automatic, install a transmission fluid cooler.

If you're still hot, you'll probably need the radiator "rodded out" or replaced.
 
Make sure the block is flushed out and running clean. Check your water pump to make sure the impeller is actually turning on the shaft. Hoses? Clean and open. Just sayin'.
 
8) you guys are forgetting that he is reading 190 at the radiator, and the head which means the engine is likely not overheating. the first thing to do is replace the temp sending unit with one designed for a gauge and not a light. if that does not solve the problem, then check either the fuel or oil pressure gauge and see if either one of those is also giving a funny reading. my 66 mustang temp gauge would start climbing, and at the same time my oil pressure gauge would start dropping at an equal rate. when i replaced the instrument voltage regulator, located on the back of the instrument panel, that problem went away. also look for a bad ground as well. my old F250 would spike the temperature gauge when the lights were turned on due to a bad ground.
 
great reply, that is one of the things i was thinking, the only oyher gauge i am using is the fuel gauge that runs off the regulator and it seems ok no crazy readings going to try a different gauge once i replace the rad, thanks. do these 200 run hot, what temps are you running
 
engineer36,
8) If you switch to a mechanical gauge, I would put it in a pot of water and read the temperature when it boils. Double check it for accuracy in comparison to the temperature that water boils at your elevation.

This is something that I wish I would've done because I was trying to troubleshoot elevated water temperatures on my rebuilt engine and I still don't think I can fully trust my mechanical temperature gauge.:roll:

Stephen
 
190 does seem normal. If its fine till you shut it off I would be looking for a lack of pressure and making sure you have the proper coolant mix. Temp always spikes when you shut down. The pressure in the system and coolant mix raise the boiling point to over 230 so it gives you some headroom.
 
thanks for the reply, i like the idea of testing the gauge with boiling water will definitly do that. i have a 13lb cap on rad now. what dictates the pressure in the system besides temp
 
The amount of air you have in there. Purge as much as possible and leave only a half inch or so below the filler.
 
lagrasta, i like your response the best, your right im probly just being paranoid cause this has been a 3 year project that was costly. im gonna flush sys., install new rad and gauge, and enjoy thr fruits of my labor, pics to come as soon as i figure out how to post em. when i get off duty beers on me
 
There are radiator flush out compounds available. You pour them in and they boil away the rust in the block as you drive it for a little while. Then you drain the whole system down. You have to get a big enough hole for chunks to come out so don't do it with the drain valve on the radiator. You would want to loosen the lower hose at the block and flush it out with a hose on the top end of the block. When it runs clear, you are good to go (pretty much). Then flush/drain the rest of the system and refill to spec with coolant and water. Some guys add "water wetter". This helps the heat transfer to the water/coolant mix more quickly.

Since you are replacing the radiator anyway, you could do the flush out of the block just before you hook up the new radiator in place.

Once all that is done, you want to run the engine until it heats to operating temp and bubbles quit appearing in the radiator. This will actually take a little while. Then fill to within 1/2" of the filler and button it up.

I had a boil over problem for a while. I finally got the right fill level by observing the air purge with the radiator cap off. Once that was done and bubbles quit appearing, it was all good. The problem was the entrapped air in the block that had to move along and it doesn't come out all at once as you fill the system.

What makes this more complex than you think is that the thermostat opens when the coolant temp gets high enough to open the valve. HOWEVER, it is the temp of the coolant on the BLOCK SIDE of the thermostat -- you know, the side where the AIR is trapped. Not the water on the radiator side, because this just sits there, outside the block until the thermostat valve opens. You know when the thermostat has opened because there will be a rush of warm water in the radiator and the block temp will go down quickly. A little later a large blob of air will come up and the coolant level will drop quickly, But you have to keep waiting until ALL the air has bubbled up to the top of the radiator. You have to keep on filling until it stays at that level. That is why it takes a little time.
 
8) one thing you can do to help remove air from the system without running the engine, is to drill a 1/8" hole in the thermostat, and position that hole at the top when installing the thermostat. it wont purge all the air from the system, but you can get most of it out and prevent a lot of problems.
 
rbohm":2x5ou5f8 said:
8) one thing you can do to help remove air from the system without running the engine, is to drill a 1/8" hole in the thermostat, and position that hole at the top when installing the thermostat. it wont purge all the air from the system, but you can get most of it out and prevent a lot of problems.
Click to expand...

That's exactly what I did on my Falcon.
 
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