dg95677

I have a 2001 Ram 2500 Cummins H.O. I was driving home the other day with the heater on, and all of a sudden cold air began to come out of the interior vents. After I got home and looked under the hood, coolant was leaking from the passenger side of the engine area near the radiator. I could not detect any noticable hose breaks, radiator damage, etc. After the engine cooled down, I checked the radiator and found it to be empty. But also noticed the overflow canister to be full. The temerature on the temp gauge never rose above the normal range. Could this be a sign of a bad thermostat?

ArcticWolf

It could be that or your water pump has gone south. Another thing you might check is your belt, if it's old and worn, it might be too loose and this could cause your waterpump to slip, overheating the coolant.

Haulin_in_Dixie

I can give you a couple of pointers that I have learned along the way. If the overflow stays full, you have either a leak in the tube that feeds it or a good leak in the cooling system that does not allow the vacuum to pull the fluid into the radiator.

The temperature gage does not register engine temperature. If there is not circulation the gage will not register the overheat. It registers water outlet temperature and is not in the water jacket with the head, but on the other side of the thermostat. I lost an engine twice because of this problem. Will be adding a temperature gage that registers head temperature.

Crawl under the truck on the passenger side, near the rear of the engine, look up from the bottom at the engine, up the side of the block and see if you have leakage there. This is important, if you do you have problems. Look at the head where it connects to the block, at the front of the truck, on your left side, see if there id leakage under the thermostat portion of the head. That is where the head gaskets like to leak. Also at the rear of the engine on the other side.

There are two water pumps in use. One has a bleed hole, generally about half way down the side on the drivers side of the housing, it is 5/16 or so maybe larger. See if that is leaking. The other type has no hole but has a depression in the casting of the water pump where it bolts against the block. At the bottom of the water pump where it bolts to the block, there could be leakage this is where the bleed hole is on that type, you cannot see it with the pump on the truck, but will leak from the bottom of the casting and the block.

other than a radiator leak or heater core leak, the other common place to leak is the steel tube that comes from the lower radiator hose housing and goes to the top of the intake manifold to feed the heater hose. It likes to rub on steel parts and wear through.

Haulin_in_Dixie

I forgot to mention that if you cannot find a leak, look for a bad head gasket with a compression leak. To check this, full the radiator completely, run it some to get the air out. Take the radiator cap off make sure the water is full to the neck of the filler and look for bubbles. If the head gasket is leaking it will build pressure and push the coolant into the overflow, until the radiator is empty and the engine overheats. First clue is an over full overflow bottle.

I added all this stuff because you obviously did not see a leak or there would not have been good reason for the post.

Stamey

Wow HID, I'm gonna save this good info for if I ever have a problem. Thanks for the experience.

Chris

ratsun

It sounds like HID right on the money.
Coolant leak observed at the front PS rad area was most likely from the over flow bottles overflow. Sounds like a HG to me, I would do a comp or leak down test to see. Keep us informed and good luck.

Haulin_in_Dixie

The 24 valve trucks can be checked for a head gasket leak just like an old gasser v8. That is how I checked mine and it does tell all. To do this take off the fan belt (serpentine). Take the thermostat out but leave the coolent in the engine. It should settle down and drain to where the neck is full where the thermostat goes. Start the engine, if it pumps bubbles up through the thermostat hole, start taking the head off. Of course don't run the engine long enough to overheat it. A minute or two will tell. Generally bubbles will boil up out of the thermostat housing if the gasket is bad.

Mopar1973man

I agree with HID!

I did a head gasket on a V6 Dodge car. It seem to me that the own overheated the engine in the same manner. The overflow bottle was always full! It would blow all coolant out of the engine. Compress test on that engine showed that it blew the gasket between the cylinders.

So to make a long story short... Resurfaced the heads and new gaskets! I made $300 on the deal!

Palmetto_kid

HID,

Where will you tap into the head for your temp gauge?

Haulin_in_Dixie

On top of the head there are a series of npt plugs. As mine took out the number one cylinder first, I will use the front most plug for the mechanical probe. Have the fittings, just need the time to hook it up. Further back one of these plugs are used to feed the heater hose.

dg95677

I just got the truck back from the dealer. They said it was the thermostat that stuck closed causing the vehicle to overheat. They replaced the thermostat and the truck is running great.
Thanks for all the info. This is my first diesel, so all the info. was very informative and very helpful. Thanks again.

Tazman

HID,

I like the idea of getting true temps in the head.

Do you know whether the existing probe/assy can be relocated?? or is it an entirely new probe & gauge??

Haulin_in_Dixie

The engine is electronic and the temperature setup is part of the programming. I would not fool with it. A temperature gage is cheap, you need one with a 90 inch probe and it will reach from the head to the inside. The front most hole is a 1/4 npt which is where I am mounting it.