I've never been so happy to find something wrong with my car! (Running warm)

[Jim Saraceno]

Well it has been quite a while since I've been on here. Ever since I've owned my '35 it has has a tendency to run warm. If it is less than 80 degrees outside, I can drive her all day and not have a problem but as the temp starts creeping up from there, so does the engine temp. I had a long thread about a year and a half ago and there was much discussion and many hints... http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=26054&highlight=running+warm

As it is only a problem when the weather is hot enough that I'm unlikely to drive it, it has been low on the priority list. I had always thought it was the radiator but when I did the flow test according to the shop manual, it passed with flying colors. I finally decided to pull the radiator and take it into a radiator shop and see what they said. I just talked to the guy and he said he's been boiling it, flushing it, back flushing it and has been getting "mud" out of the radiator. He's going to let it soak over the weekend and flush it again.

Halleluiah! We may finally have a solution here! I still can't understand why it would flow properly if there are blockages. Of course I won't be sure I've solved the problem until next summer when the temps start getting up into the upper 80s.

One question for you guys. Several times when I drained the coolant from the car, then refilled the system; I would start the car, run it for a while and the temperature would shoot up and overheat. I'd turn the car off and let it cool then everything ran fine after that. I'm thinking I had an air pocket somewhere that needed a "burp". How do you prevent that from happening?

[Mark D]

Sounds to me like your radiator sludge was fouling up your t-stat mechanism preventing it from opening. Boil overs usually occur when there is a blockage in the flow of the cooling system.

[TodFitch]

... One question for you guys. Several times when I drained the coolant from the car, then refilled the system; I would start the car, run it for a while and the temperature would shoot up and overheat. I'd turn the car off and let it cool then everything ran fine after that. I'm thinking I had an air pocket somewhere that needed a "burp". How do you prevent that from happening?

Good to hear that there is now an explanation and probable cure for your car running warm.

My car is fitted with an after market heater that has a drain valve on the bottom and a bleed valve on the top. I find that I can purge the air from the system after refilling it by opening that bleed valve until some water comes out.

Not sure what would work on a stock system. I think the air is being held in by the thermostat and the thermostat won't open well unless it is wetted by the coolant. Maybe running the engine for just a minute or two, just enough to get things a little warm, and then shutting it off and allowing the heat in the castings to slowly warm the thermostat enough to open and let the air out...

Edited November 15, 2012 by TodFitch
Hmmm. Four letter word for a drain valve seems be consider bad.

[Young Ed]

Maybe your radiator has the same issue as my kitchen drain

Honestly I think that measurement for flow testing is greatly understated. We had one that passed that test also and the radiator was 1/2 full of mouse nest.

[Oldguy48]

I have not tried this myself, but I've read that a small hole drilled thru the edge of the thermostat will allow any trapped air to pass thru when the thermostat is fully closed, but won't impair the normal operation of the thermostat.

[desoto1939]

OK I did a search on how to burp the radiator. Below is the link based on a modern car but the process should still be the same with our antique cars/trucks.

http://wiki.answers.com/Q/How_do_you_bleed_or_burp_air_from_the_engine_cooling_system_on_a_Ford_Windstar

Rich Hartung

Desoto1939@aol.com

[RobertKB]

Jim, if you haven't already, remind your radiator guy that these old radiators where unpressurized and should not have much pressure applied to them to check for leaks. 3-4 pounds might be OK, but no more.

[RobertKB]

Maybe your radiator has the same issue as my kitchen drain

Ed, that is disgusting and should get you banned! LOL:p

[Plymouthy Adams]

ah come on..Ed is doing what needs be done..he has the skill..save the ton of money the plumber is going to cost you less the butt crack...that alone is worth it....that was a bit worse than the 8o gallon grease trap on my old house..last month was the third time I have cleaned it in 18 years..I think that is more than good service..

kitchen drain lines are always a bit of a mess...

[james curl]

No only kitchen drain lines but washing machines also, especially if the line doesn't have a lot of drop. It fills up with what looks like Crisco from the soap. Years ago in another house while the wife was out shopping I rented a pressure plunger that used a water hose to supply water. I pumped it up to close to 100 pounds ,stuck the soft rubber boot into the drain and pulled the trigger. The obstruction was gone. When I went into the house the kitchen was covered with the nastiest black goop including the ceiling. The air pressure blew the strainers out of both sinks bowls and cleaned the pee trap plumb clean. Took a couple of hours to clean the kitchen up before the wife got home, learned a good lesson, open the clean out before attempting this operation.

[chopt50wgn]

To help prevent getting that air bubble trapped .............I work for a hot rod cooling company...........I tell my customers to remove the thermostat housing and pour about a gallon/gal &1/2 thru the manifold to fill the motor from the bottom up. Then you can put the housing back on the fill the rest in the radiator.

When you fill solely thru the radiator you chase an air bubble into the block and it may get stuck at the pump or somewhere in the block. The only way to remove it is to "cycle" the motor.......get it hot, let it cool down........after a few times of cycling ,the bubble should have worked its way out.

[Young Ed]

Anyone heard of proping the thermostat open with a couple asprin? I've never tried it but supposedly it keeps it open while refilling and then harmlessly dissolves.

[Jim Saraceno]

Thanks! I think I'll start by filling the block before I install the stat and housing. The aspirin trick sound intriguing also. I may try that just to see if I can make it work. I've also heard of drilling a hole in the stat but I'd rather not. It may work but I'd be afraid I might compromise the function of the stat. I think I'll give the radiator guy a call and remind him he's dealing with a non-pressure radiator. He seems competent enough but it never hurts to play it safe.

Ed, hopefully I don't have any mice in my radiator.

Thanks again for all the input!

[Adam H P15 D30]

Easiest way I found was to remove the heater hose at the rear of the head. Fill radiator until coolant comes out of the heater hose connection. Reinstall and top off. Minimal air

[Young Ed]

Thanks! I think I'll start by filling the block before I install the stat and housing. The aspirin trick sound intriguing also. I may try that just to see if I can make it work. I've also heard of drilling a hole in the stat but I'd rather not. It may work but I'd be afraid I might compromise the function of the stat. I think I'll give the radiator guy a call and remind him he's dealing with a non-pressure radiator. He seems competent enough but it never hurts to play it safe.

Ed, hopefully I don't have any mice in my radiator.

Thanks again for all the input!

Jim if you're up to it I'd like to hear the results of redoing the manual flow test where you observe the column of water. I suspect you will notice what I did that the column is a lot higher than before.

[drillmastertommy]

1 or 2 1/8" holes in the thermostat works a treat. Did it with our 235 stovebolt, my 59ab flathead and my 218 Plymouth 6. Avoids the possible air pocket without the issues of not running a thermostat and from the research I did before doing mine it seems to be recommended.

[Jim Saraceno]

Jim if you're up to it I'd like to hear the results of redoing the manual flow test where you observe the column of water. I suspect you will notice what I did that the column is a lot higher than before.

I try to do that when I pick it up.

Easiest way I found was to remove the heater hose at the rear of the head. Fill radiator until coolant comes out.

That's another good idea.

1 or 2 1/8" holes in the thermostat works a treat. Did it with our 235 stovebolt, my 59ab flathead and my 218 Plymouth 6. Avoids the possible air pocket without the issues of not running a thermostat and from the research I did before doing mine it seems to be recommended.

I'm sure that will work. It makes sense and I can't imagine that it would be a problem but it just goes against my grain to drill a hole in something that I don't have to. If it was necessary, they would manufacture them with holes in them already.

[Niel Hoback]

Jim, I have used bought and used new stats with a small hole already in the valve. It was obvious why the hole was there. The hole is smaller than 1/8". When you pour in the coolant, you can hear air bubbling up through the top hose.

If you're in a real hurry, take the top heater hose off at the heater anD fill until it comes out. That is the highest point in the system.