Engine/Transmission (1994 - 1998) Erratic temperature& blown off radiator hose

[KYOUNG]

Just spent a week up at Algoma, Wisconsin pulling my toy hauler with the wife and Grandbrat and was coming home and shut off to get Subway and Lower radiator hose came off of radiator soon as i shut it off. This is the 3rd time in 8 months that it has done this, once while driving down the road. I have replaced the thermostat, both hoses, the radiator is about 3years old, and this time i double screw clamped the hose on the radiator and tossed the spring clamp.



After fixing this in Subways parking lot and getting back on the I 44 going home the temp will run at 190 than jump up to about 215 for a while and than back to 190. Is this a bum Thermostat? Since I changed it last fall the truck seems to run alittle warmer than before and fluctuate to the high side alot. My past ones would open and close alot cooler than this one is. ???

 

[hsmith]

Strange that the lower hose is coming off. The upper is the one under pressure normally. Did you use a Cummins stat?

 

[ScottLewis]

Replace the radiator cap. They are designed to vent excess pressure and it may be faulty.

 

[Skydiver]

The radiator has two lips where the cap attaches. Remove the radiator cap while it is cool and let it idle with A/C on while keeping the water level up even with the bottom lip. Do not allow the water level to fall below the bottom lip. Keep adding water as needed. After it reaches operating temp do you see any small/tiny bubbles coming out? If you see bubbles they are coming from a compression leak. Another thing you can do if your cap is operating properly. While up to operating temp. look inside the coolant recovery jug while the engine is running. See any bubbles?

 

[fox]

Head gasket blown?

 

[B.G. Smith]

I agree with danavilla, the cap is probably bad and sounds like the thermostat is defective too. Sounds like what is happening is the temp. in the block is above boiling point of your coolant and when you shut the engine off the coolant boils some and blows the hose off. bg

 

[Extreme1]

Sounds like the cap might be bad but it is still getting really hot. Is the fan clutch working?

 

[KYOUNG]

new cap on it. I am thinking that the hose is being pulled off from a vacuum, maybe the thermistat housing bypass is stopped up. bottom hose draws coolant out of radiator into pump thru motor out thermistat to top radiator hose.

 

[Missouri Mule]

Usually the t-stat opens up at 180 (mine will stay at 190 running down the highway sometimes instead fluctuating) the fan should kick on some where in the 200 to 215 range. (Don't have my service manual with me to tell you what tempature exactly. )