Had a little problem come up today, I had to pull my Jag out of the garage to change the oil in my Tahoe. I let the Jag set running for a while(15-20 min.) to let it warm and remove condensation that may have formed. I store it in winter. I pulled back into the garage and noticed steam coming from the engine. Shut it off popped the hood and fans were running. found that the upper radiator hose had come off at the thermostat housing. checked the hose and housing found nothing wrong. Put the hose back on with the original clamp, started it and let it run few minutes while revving a little. All was fine. So anyone got any ideas of what may have caused the hose to blow off? The engine never did get above normal operating temp. Could there have been some air in the system that caused it to overpressure?
thanks,
Dave

 

I have had that one come off as well- the barbs on the plastic Thermostat seem to get worn and let the hose slip off- I just tightened the clamp and it was fine from there. Might want to replace the hose and Tstat cover as well- it will provide some additional insurance against it happening again and is a maintenance item anyway.

 

I would try "burping" it as well. Air expands much more than coolant with heat. So, the more air in the system, the more pressure (with heat). There are posts on here about "burping" the system. Basically you need to remove the cap on the thermostat tower and get all the air out of there, but there are more detailed instructions somewhere. I wouldn't trust the temp gauge either though. Many posts on that too, as you probably know.

 

Dave....an all too common fault I'm afraid.
Fix this by running a piece of Emmery cloth around the thermo cover to give it some grip.
Replace those awful spring clamps with two worm drive stainless clamps....end of problem.
Using two narrow clamps gives a greater clamping area where the hose fits over the thermo cover.
While you're at it, replace the other major hose clamps with stainless worm drive clamps.

 

Third one of these we have seen this month. See CVELLA overheating . . . , JHARTZ radiator hose separation.

One with spring clamps, one with stainless screw type . . .

I think it is the very cold weather and effects on plastic pipes and rubber hoses. But as SEANB noted, keeping a close eye on the thermostat . . . .

Since replacing my hose and refilling and burping the system I have had no more issues and am keeping my fingers crossed - thermostat is opening starting at 185F and fully opened by 195F, fans are coming on at 203F and off at 197F. 10 inches of snow and 11F, unheard of here in Tidewater Virginia.

 

It seems to me that having the hose blow off would indicate a good opportunity to replace the plastic housing with a metal. I would not feel comfortable using the old one after having that happen.

 

Yes, I would recommend the same. Aluminum termo housings are readily available and the way to go over the OEM poly housing. (99 percent failure rates) It is possible that the themo housing is going. My main hose blew off after a piece of the housing broke off and I found it inside the hose. Clamps may be one thing but very possibly more is going on especially if the housing is original.

 

Thanks for all your replies to my post. They are greatly appreciated. Today I got new antifreeze and couple worm gear clamps. I installed the hose, filled, warmed, and burped the system. Run and revved a few times and all seems to be ok for now. Checked for any leaks and ok. I am going to replace the plastic housing(been thinking about that for sometime just waiting until I flush the system). I will be rechecking every so often for now to see if it happens again.
Thanks again,
Dave

 

I would like to say a couple of words in defence of the plastic thermo housing.;o]

The system as designed works well and my own car is proof of that.
What let's it down is the human condition of "touch nothing until it fails"
Most problems experienced with the original plastic components is down to LACK OF REGULAR ATTENTION.

It seems to be quite often that these systems are let down by a lack of proper and due dilligence by both the service people and the owners.
Service people take short cuts and owners won't or don't want to spend money.

My own car travelled over 200,000klm before I deemed it necessary to replace the original with the alloy components and this was only because a hair crack developed in the main body of the therrmo tower which only showed up under heat.
Even with the new alloy components installed, I still use two worm drive clamps on the thermo cover to inlet hose connection ;o)

 

A fair point but I think the plastic used in the cooling system was not a good idea. The very first day of ownership I was driving the car home from the PO and "pop" , steam everywhere. Yes the top hose had come off, yes it was cold and dark and I was eventually rescued by RAC - not a great confidence booster for X308 ownership !
I replaced the plastic thermo housing with alloy and double clamped as suggested before.
Also, while swapping out the water pump later I noticed the plastic thermo outlet pipe had quite severely corroded where it connects to the top rad hose. There were quite a lot of plastic specs in the coolant which must have come from there. Needless to say this was replaced also...

AndyP

 

My hose came off at the radiator end; still, I will look to replacing the thermo housing.