Still running hot, frustrated and need ideas

[White Spyder]

I had a 40 mile run today to a show, the first since my water tube change out a month or so back. At that time I did a through flush of the radiator (replaced when I got the car 3 years ago with a new 2 core), block including removal of the welch plugs on the driverside to remove the sludge. After about a 20 mile stretch at 55mph the temp was just under 212 on the gauge. I slowed down and the temp dropped to around 190 and stayed as long as I was going no more than 45mph. The thermostat is a 180.

Once I got home I checked the Fluid in the radiator and it looked clean and the pump was moving good volume. I got a gem from my linfared of 190 at the neck of the radiator but was moving at less than 45mph.

What could be keeping it running hot as I go over 50 mph? Only thing I can think is that maybe it is not advancing correctly and running lean. However, I do not seem to be having any performance issues that would confirm my thoughts.

Any other ideas?

[Robert Horne]

Look in the radiator when the engine is running and look for any tiny bubbles.

 

I had a little Chevy van in the 60s that would heat up on the freeway, but

 

would cool down on the secondary roads, or stop and go traffic.

 

I had a head gasket problem..

[Jeff Balazs]

Have you tried running a 160 thermostat to see how it behaves?

 

Jeff

[P15-D24]

Run the 160, that way it will be at 190 under load. You giving up 20 degrees of cooling headroom by running the 180.

[55 Fargo]

Certainly a switch to a 160 may help alleviate some of your issue, but no guarantee, 160 t/stats open at around 155 degrees and will be fully open at 175-180. The cooling system if there is a problem will continue to get hotter temps rising up to as you have described.

I would lookat your rad again, and the lower rad hose for issues associtated with collapsing under higher RPM on the highway.

So here is a checklist,

- clean water dist tube

-no restrictions in the block and water passages

-t/stat confirmed to work correclty

-water pump flowing/pumping

-lower rad hose

-rad has good flow

-timing is not too late

-dragging brakes

-higher engine loads caused by higher RPM load etc, creates a lot more engine heat

I fall is well in these categories, you should have a decent cooling system and engine not running too hot.

Head gaskets leaking into the water jackets, can and will make things hot

Heat Riser flaps, frozen in the wrong position can help under temps too, not being causal, but certainly no helping matters.

Good Luck, and I hope the T/stat change corrects your engine heat problem, but I am not holding my breath on it......

[mopar_earl]

Keep a 180 t-stat and find the real source of the problem. Is your temp gauge accurate? Do you have the correct type of t-stat? Is your lower hose collapsing under load? Water pump impeller slipping? Belt slipping? Fluid drive coupling have the correct fluid and level? Plus what fargos said.

Car shouldn't run hot on a 180 stat unless there is a problem with the system.

Earl

[stan's52]

I was going to say the bottom hose is being sucked shut, but someone else beat me to it. I would drop the level in the radiator so you can see the tubes through the filler neck. You can only see a few tubes. See if any

are plugged. If so that means a lot more are plugged. Even though the radiator isn't very old. it my be plugged from the

block being cleaned. Stan

[soth122003]

When I had a 180 t-stat in my P-15 my car would run at about 190-200 at speed. I switched to the 160 and my temp stays at 170-180. That being said. What is the flow rate of your new radiator? Is it an after market? The purpose of the t-stat is to regulate the flow of water. If your radiator lets the water flow to slow from being clogged up you will overheat. The same goes if your radiator is a straight flow radiator. The original rad's were honeycombed to allow water to flow at about 20 gpm. This allowed enough time to cool the water as it passed through.

 

As you speed up the water pump moves the water faster through the system. For me the answer was a good flush and cleaning of my original rad and a 160 t-stat.

 

In the manual, it states that the 180 t-stat is for cold weather conditions. The normal t-stat was a 160 for Plymouth cars from 1946-54. You should use your IR temp gun to check the engine at all areas along the water flow path to check for hot spots and possible clogged water jackets.

 

Joe

[55 Fargo]

When I had a 180 t-stat in my P-15 my car would run at about 190-200 at speed. I switched to the 160 and my temp stays at 170-180. That being said. What is the flow rate of your new radiator? Is it an after market? The purpose of the t-stat is to regulate the flow of water. If your radiator lets the water flow to slow from being clogged up you will overheat. The same goes if your radiator is a straight flow radiator. The original rad's were honeycombed to allow water to flow at about 20 gpm. This allowed enough time to cool the water as it passed through.

 

As you speed up the water pump moves the water faster through the system. For me the answer was a good flush and cleaning of my original rad and a 160 t-stat.

 

In the manual, it states that the 180 t-stat is for cold weather conditions. The normal t-stat was a 160 for Plymouth cars from 1946-54. You should use your IR temp gun to check the engine at all areas along the water flow path to check for hot spots and possible clogged water jackets.

 

Joe

Joe, yes of course you would run at 190 with a 180 t/stat, as it would be fully open at 195-200.

The old recommedation of 160 summer and 180 winter was 2 fold, the obvious, winter is much colder, and the use of alcohol based antifreeze and a 180 t/stat in summer would boil up easier then water.

Running with a 160 t/stat and an engine operating temp of 170-180 is fine, and 180 is probably optimal.

But with a problem in the cooling system, even a 160 t/stat will not stop a hot engine condition, just allows the water to get into the rad at a lower temp.

The OP can try this out and see what happens, but I suspect other issues if his engine is going up to 212 and beyond, the 180 t/stat should have kept him in the 190-200 range on hot days.. PS operating an engine at 160 is not optimal, and will create more wear, 180 is definately the optimal range to shoot for, but to each their own

Edited October 24, 2015 by Fargos-Go-Far

[Plymouthy Adams]

a thermostat is only as good as the ability of the system to absorb and exchange heat..find the real problem...pressurize your cylinder one at a time and observe the reservoir

[Don Coatney]

A compression and leak down test will also be helpful.

 

[Plymouthy Adams]

as Don posts the chart yet again...simple diagnostic test folks...WHILE IT MAY NOT show you what is wrong..it will at the same time prove what is right..both are items of great value when known to you..

[White Spyder]

Thanks for the replys.

 

Don, I will have to get a compression guage and fab up a sparkplug to do as you suggested.  Will hit the store today.

 

Since my first post this is what I have done and found.

 

1) Checked hoses.  They were all replaced a couple of months ago but still look good and as I rev the engine they did not collaspe.

 

    

 

2) Checked heat riser and found this.  Is the tang suposed to be exposed lik this?

 

    

 

3) Pulled all the plugs and they all looked like this:

 

see next post

    

 

4) Radiator appears to be unobstructed. I get good flow at the petcock.

 

5) Checked oil and it does not appear to have any water in it, no frothy brown chocklet at the filter.

 

    

Edited October 24, 2015 by White Spyder

[White Spyder]

Here is the plug photo:

 

[Plymouthy Adams]

4) Radiator appears to be unobstructed. I get good flow at the petcock.

 

Flow at the petcock is a trickle compared to the exchange you supposed to get throughout the radiator....and if your radiator is full the very height of the water above the petcock is adding pressure due to gravity thus its flow will be likewise a bit healthier..

 

check your book..the test for a radiator by visual is given there..again this is just a visual..only a flow test can measure the capacity..I not long back posted how this can be done at home with an accurate result...

[Don Coatney]

When you buy a compression tester make sure if you get the screw in type that you don't get one with the long reach. You need one with the short reach so it does not thread so far into the head that it contacts and bends the intake valve when cranking the engine.

 

http://www.langtools.com/sku-tu-30a-compression-tester-set/

[soth122003]

You can check harbor freight for a comp tester. there not a bad product and cost about $30. As far as a t-stat, your choice, The thing I was trying to point out was water flow through the system is supposed to be a set rate of flow. To fast or slow will result in higher temps.

 

Joe

[captden29]

test the flow of the rad. like this have someone hold their hand over the bottom outlet. fill the rad, and then have the hand quickly removed from the bottom outlet. water should shoot upwards about 8 to 10 inches for proper flow. I did mine on a table to make it easier. capt den

[White Spyder]

Here are the compression numbers.  Engine cold, 74,600 miles on the clock and never been into.  251 ci in a Crysler Windsor.

 

cyl 1 94 psi

cyl 2 88 psi

cyl 3 68 psi

cyl 4 88 psi

cyl 5 86 psi

cyl 6 84 psi

 

Still fabbbing up the leak down tool.

 

With the way the plugs look is it possible that it is leaning out too much at higher speeds?

Edited October 24, 2015 by White Spyder

[Plymouthy Adams]

If I were a guessing  man I would say a leak of 3 and 4 to the coolant passages due to blow gasket..but yes do test prior..

[dale]

Bad temp gauge ?

[White Spyder]

Delay in prognosis due to work travel. I'll be back at it this weekend.

[Charlie Stephenson]

Have you painted the 2 pass radiator with to much high gloss black paint ? The flow test with the radiator on a bench -- measure the amount of water that comes out and how long it takes. This would be a gravity test not water pump assisted. Don't expect 20 GPM but it may give you a gut instinct on the flow. I liked the 8 to 10 inch gush method, my gut tells me that is a good flow, unless it only takes .5 seconds for the radiator to gravity drain. Air will NOT release from a water stream flowing at more that 1500 feet per minute, this I taught. You could find a water pump repair shop that has a water flow meter and series the flow meter in your radiator hose circuit, I'm trying to buy a 5 GPM to 80 GPM flow meter to provide that service in Des Moines, IA. New ones are out of my price range. My "33" (while stored) was without the Flying Goddess radiator cap and a family of mice moved in and it won't flow water at all. So much you gota know----- ? I believe I wouldn't even consider selling the P15 lol. Hang in there you and all of us will get it fixed together.

Charlie

[Charlie Stephenson]

If you suspect to much water flow through the 2 pass, go  to your Big Box Lumber yard and get a PVC valve,  insert it in the top hose and slow down (regulate) the water flow.  Or just pinch off the top hose with Vice grips.  The valve would be less trouble because you could paint it Black and levee it in place.  Same idea as the T-star as a restrictor.

 

Charlie

[White Spyder]

Work diverted me to Houston. No opportunity to work on this issue for a bit.