UPDATE! Runnin Hot
Thanks Mike,

I am no expert on this and am mostly parroting what I have heard and read after experiencing the Cleveland run hot issues.

It has to do with the Cleveland "dry" intake which does not allow crossover and consequently will not vent out trapped air. The Cleveland specific thermostat allows the block to vent out that trapped hotspot.

I know that manufacturers will list parts as fitting in that they do fit but are not aware of intricate and subtle differences.

Hi 1969M1, 'Tick over' = 'Idle' (English term). Using a restrictor will simply slow the coolant flow at all engine speeds. If the flow is too fast the coolant has no chance to absorb the heat so the engine will boil.
Correct flow rate for all temperature states, with good coolant, in a well maintained balanced system is what we are aiming for.
M1FF, I guess I should have said, how does the restrictor work in a Cleveland if it takes a specific thermostat to work properly.

Well, I learned something here about Cleveland specific thermostats. I hope the OP reads all the posts before proceeding.

Alright fellas here is the Mr Gasket 4363 T-Stat I got that 1969_Mach 1 told me about. It has the cupped shoulder like the Robert Shaw ones.


From what I understand (and I'm no expert by any means) they work like this:


I'll get it put in after I get the kids squared away and well see whats up.

Quote:I've heard the China imported radiators of equivalent sizes have less coolant capacity.

Im not sure. It was replaced in 07 I do know since I saw it on a invoice. I'll see if I can figure that out.

If this doesn't take care of it I'll pull the pump and check it. It does seem to be pumping water but maybe the impellers are jacked up.

Thermostat totally fixed it!

I did basically the same drive as yesterday but added a few twists and a heavier foot and the results were pretty obvious. The temp gauge never got higher than just past half way and that was after hitting on it really hard, for really long and then sitting at a really long light. Once moving it dropped right back down past half way and pretty much stayed there going up slightly at longer stop lights. I was running the AC the whole time as well. Once I got home I shut it down and ran inside and grabbed a beer and talked to the wife for a few minutes (30 or so). I went back out and fired it up and it was pretty hot (which I expected). A quick trip around the block cooled it right back down. Then I let it sit and idle (with the AC) for a while and it stayed just past half way (far right of the "M"). It was noticeably cooler in the car as well. I think its good guys.

Thanks everyone for the replies. Was super helpful.
Great to hear! I keep an extra thermostat and gasket around for all my vehicles. Just so I don't have to run to the parts store when I need one.

30 years ago all standard thermostats looked like todays high flow models. I guess they found a less expensive way to make todays standard thermostats.

After going through all these same pains with correct thermostat, water pump, radiator, and timing and tuning, I finally checked and replaced the head gaskets trying to get my Cleveland to stop vomiting after a short 5 mile drive.
I was finding that my coolant was being pressurized somehow.
It even blew out my brand new heater core which is a royal pain to change out.

Either I had slipped a main bearing or I had a likely crack internally in the block was my guess.
I had checked the heads out carefully when I cleaned them.

With Fords thin walled castings you may also have a crack in a water passage.

Check your oil for signs of coolant in the oil.
Check your coolant for signs of oil in the coolant.
Have your mechanic check the gases from your coolant for signs of exhaust gases in the cooling system. There is a meter that can detect this.

I ended up getting a new Cleveland crate motor.
So I have had no overheating issues since the T-Stat change. However last nite I came home after a quick trip and saw some foamy coolant on the ground. I opened the cap and it looked like foamy chocolate milk. I checked the oil and it is as clear as when I changed it last week. I pulled the plugs and did a compression test and all were 120 except #1 and it was 100. Car never got hot and ran just fine.

You guys think its the head gasket or should I assume the worst? This is my first Cleveland so any specific stuff I should check before tearing it down?
No specific stuff comes to mind it looks like you're for a tear down. Head gasket is a possibility, along with a cracked head, or even a cracked block. With the compression low on 1 cylinder, I would lean toward the head gasket, be sure to have the head checked for cracks, and for warpage. While Cleveland s are not really known for these problems they did have some issues of block cracking, in the early years. Let us know what you find and we'll give some more ideas as to what is really going on. JTS 71 Mach1
Kinda what I figured so I went on and started tearing it down. I'm going to get the heads off and take them for testing...do the gaskets and see whats up after that. I haven't replaced a head gasket in years so I'm actually looking forward to it. It'll be a good time for the boys too.

I'll keep y'all posted.

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