I have a cat 252b that I am having problems with. The coolant is bubbling in the overflow reservoir and overflowing. So far I put a new radiator cap on it and I checked it for combustable gas, which it tested fine. Any ideas for me to try?? Thanks
There are Guys on here that have much more experience than I do with heavy equipment, but the only time I have seen this in a vehicle it was caused by a head gasket issue.
I thought about the head gasket so that is why I did the combustible gas test and it tested fine.
YEAR? SERIAL NUMBER!!!!
I am not familiar with that test , as I said there are other people on HEF with much more experience than I have. I can only share what I have experienced in the past. when you figure it out be sure to post it so I can learn from it. Sorry that I couldn’t help you with this one.
Bobcat Crazy, it is supposed to test for bad head gaskets or a cracked block. It checks for gases being pushed through the bad head gasket in to the coolant system. Thanks for the info though! 512high: Its a 2005, serial number Scp02297
If you can get hold of a cooling system pressurizing pump try pumping the pressure up to at least the radiator cap pressure (8psi minimum) rating when the engine is cold and see if it holds up. As BC pointed out the obvious conclusion is a head gasket despite the fact the test for combustion gas in the coolant came up negative.
Nige, thank you for the info. I will see if I can get a pressurizing pump. If the head gasket was bad, shouldn't I have coolant in the oil or combustion gas in the coolant?
A head gasket that is in early stages of failure will pressurize the rad but not put coolant in the oil. A pressure test of the system would be best. It is likely the head gasket.
What he said ....... ˄˄˄˄˄˄˄
Head gasket well know problem on 252
Did a pressure test on the system and lost about 0.5 psi in about 30 minutes.
Release the pressure from the gauge and run the engine with the gauge installed. Let it run until the thermostat opens or the gauge is about to peg out. If you see pressure rising quickly or the gauge is bouncing. That is compression.
I started it with the gauge hooked up. The pressure ran up to about 24 psi pretty quickly and then stayed at 24 psi, ran it for a couple of minutes.
Running it for a couple of minutes starting from cold would not be long enough to get the thermostat open. Also when you think the pressure cap is only set to relieve at 8psi it is not surprising that with a measured 24psi in the system the coolant is blowing out of the reservoir. My vote is still with a head gasket but the engine needs to be run for longer while watching the pressure to confirm.
Just wanted to update, went ahead and changed the head gasket and it seems to have fixed the problem. Thanks for all the help! The only thing I am having problems with now is I keep getting the hydraulic fluid temp alarm, keeps going in and out. Doesn't seem like the fluid is actually heating up. Does anyone know where the temp sensor for the hydraulic fluid would be? Thanks
It might be an idea to use an infra-red thermometer on the hydraulic tank to confirm the system temperature. It's not a sensor, it's a normally-open switch. It should close at 102 ± 3°C and open again at 90°C minimum. Part Number is 236-1872, location in the bottom of the hydraulic tank.
I hadn't thought of an infra red thermometer, so I will give that a try. Thanks!
With the temperature "sensing" function performed by an on/off switch there is always the possibility of a dodgy switch or a bad electrical connection producing the symptoms you describe.