951C Temp. Problem

First are there any bubbles in the top of the rad, coolant blowing out the over flow? Check the fan belts and pulleys for adjustment and wear. Then get a temp probe of some sort and check the top and bottom rad tank temps and come on back.
Later Bob

There are not any bubbles in the top of the radiator, and no coolant going out the overflow. I thought the fan belt was going to be my problem, but i tighened it up and it still is getting hot. I will get a temp guage and get a reading on the top and bottom of the radiator in the morning.

You probably should look at the thermostat as well as running a good radiator flush through the system. Probably do the flush before the thermostat, that way if it's sticking, you'll know it just has to be replaced.

Did you idle the engine down before shooting the temperatures? I'm wondering if the lower tank may have had time to cool down because of lower flow rate before you got the temps. If the engine was still running at operating speed, the water pump should have been moving coolant through the radiator at maximum speed and if it drops the coolant 65*, that isn't bad. Might need to be better though. The fact that it's taking 30 minutes to get hot means you're not far from where you need to be as far as cooling capacity under those conditions.

When you washed the radiator, did you get flow all the way through the core from your hose. If a stiff spray from a garden hose doesn't go into the radiator and not come back at you, there's some obstruction in the core still.

Another thing to watch for is if some sheetmetal is missing etc and the fan can recirculate hot air from below the radiator etc, that won't help. Also having a fan shroud missing or missing pieces could make it worse.

Is the fan rotating the correct way? Airflow should be off the concave side of the blades. Rotating one backwards so the hump of the blades is toward the discharge of the air is very ineffecient.

If all else fails, after doing the radiator flush, you can take off the top tank of the radiator and by plumbing a garden hose into the drain, you can adjust it to gently come up the flues and spill out over the top. Then you can rod out any obstructions. The flowing water will clear what you dislodge and hopefully the flush will have softened the crud up so it comes loose easily. Be gentle, even if you don't get all of them open, you don't want to damage a flue and have to repair the core after you get it all clean inside. Flush and drain the bottom tank after you get done.

It's not usually too bad of a job, just take your time getting the bolts all loose. If one doesn't feel right, try some heat on the cast iron before you wring it off. But in the end, it has to come off, so if it wrings off, you can drill it out etc once you get the tank off.

Its got a new thermostat in it. I will flush the radiator and see if that helps. Thanks.

Its got a new thermostat in it. I will flush the radiator and see if that helps. Thanks.

How long has it been doing this?

I just bought the machine and got it running. No history on it. It runs good, just runs hot.

I had to replace the core on my D6c, (many leaks) and unfortunatly I blew a lift cylinder hose right after, filling the radiator with oil. Pressure washed it out several times to get dirt/oil out, but was still running warm. Tightened fan belt, and changed thermostat and even turned down the fuel pump a little.... finally cured the problem, although I'm not sure which fix did it.

If you end up needing a new core, I got mine from RoCore and I'm happy with quality and very fast delivery.

http://www.rocore.com/AftermarketCatalog2004.pdf

I see they list your machine, but take careful measurements to be sure it matches before ordering.