Cat D6b over heating

[Sam1734]

I just put new gaskets on and the old PRV and ran it a while, about 20 minutes and the temp wouldn’t get over 190. But the coolant was still leaking from the new cap like it is overflowing. Water cool to touch in radiator. But seems to be circulating. Maybe thermostat isn’t reaching temperature to open. I’m still baffled.

 

[Nige]

Coolant leaking from the radiator cap or from the weep hole in the PRV Cover.?
Did you check that the weep passage was clear when you reassembled the PRV.?

 

[Sam1734]

Coolant leaking from the radiator cap or from the weep hole in the PRV Cover.?
Did you check that the weep passage was clear when you reassembled the PRV.?

Yes it was clear. And the radiator cap is leaking. Kind of like when you have water in a glass jar and overflowing after the engine starts

 

[Sam1734]

Kind of leaks out like a water level in a clear hose but when you look on the inside engine bay the water seems to be pouring out from the top

 

[Nige]

Radiator too full to allow for expansion.?

 

[Acoals]

Was the system ever pressure tested?

 

[Sam1734]

Just figured the main leak, the radiator cap seal doesn’t seal well so I added another thicker gasket which stops the leak but water is overflowing through overflow tube and temps getting up to about 240

 

[Sam1734]

Was the system ever pressure tested?

Not yet waiting for pressure testing equipment

 

[Acoals]

What happens if you run it at an idle at operating temperature with the radiator cap off?

Also, where did you get the new radiator cap from?

 

[Sam1734]

Only circulating and temp stays normal

 

[Sam1734]

If it reaches normal temperature the cooling rises to the rim of coolant nozzle and overflows

 

[Nige]

Again he asks, is there any possibility that are you overfilling the radiator.?

 

[Acoals]

Almost sounds like the system is air bound . . . ?

Run it with the cap off for awhile, let it find its level. Put the cap on loose and work it a bit. If everything is good it should puke coolant out until it finds its level and then stay there. Then put the cap back on and see what happens.

The cap not sealing is a problem though. Either it is the wrong cap (local auto parts store matchup attempt?) or the radiator is pitted or otherwise bad where the cap seals.

 

[Sam1734]

Again he asks, is there any possibility that are you overfilling the radiator.?

Could be. After I done the head work I refilled to manual specs which I think was 7 gallons. I don’t have the manual with me at the moment

 

[Sam1734]

Almost sounds like the system is air bound . . . ?

Run it with the cap off for awhile, let it find its level. Put the cap on loose and work it a bit. If everything is good it should puke coolant out until it finds its level and then stay there. Then put the cap back on and see what happens.

The cap not sealing is a problem though. Either it is the wrong cap (local auto parts store matchup attempt?) or the radiator is pitted or otherwise bad where the cap seals.

I will try that, and no I ordered it from regal. However it was different from the original cap. It was cast iron rather than the steel plate original. I suspect the stud inside the radiator might be bent a little because it wasn’t seating correctly. I discovered this when I removed it to check levels after I allowed the coolant to dry on the hood.

 

[Acoals]

I will try that, and no I ordered it from regal. However it was different from the original cap. It was cast iron rather than the steel plate original. I suspect the stud inside the radiator might be bent a little because it wasn’t seating correctly. I discovered this when I removed it to check levels after I allowed the coolant to dry on the hood.

Nige would probably have more insight about the cap and stud in the radiator. I have very little experience with stuff that old . . It does sound like you have the wrong cap though.

How much run time has there been since this head work?

Generally speaking the spec for coolant capacity is a reference to indicate how many jugs of coolant one should dump in before he starts paying attention . . .

 

[Sam1734]

Nige would probably have more insight about the cap and stud in the radiator. I have very little experience with stuff that old . . It does sound like you have the wrong cap though.

How much run time has there been since this head work?

Generally speaking the spec for coolant capacity is a reference to indicate how many jugs of coolant one should dump in before he starts paying attention . . .

I’ve not put over 100 hours since, just minor farm work.

 

[Nige]

All capacities listed in manuals (Cat ones anyway) are approximate refill capacities only. Systems should always be filled using whatever device the system may have for determining the correct fluid level.

I may be wrong but in radiators such as this one I thought that the correct level was just a hair higher than the top of the tubes looking down into the top tank. Enough for the coolant to circulate in other words.

 

[Nige]

I ordered it from regal.

Was it the same Part Number that you have in your Parts Manual.?
Is that the old or the new cap in your photo in Post #34 on the previous page.?

 

[Sam1734]

All capacities listed in manuals (Cat ones anyway) are approximate refill capacities only. Systems should always be filled using whatever device the system may have for determining the correct fluid level.

I may be wrong but in radiators such as this one I thought that the correct level was just a hair higher than the top of the tubes looking down into the top tank. Enough for the coolant to circulate in other words.

The radiator has a flat plate inside that the stud is mounted and unable to see the radiator.