Help me understand why only the right side hose is collapsing and the left side is perfect; this is on my '06 XK8.


Are not both upper hoses supplying hot coolant to the top of the radiator or is there a difference between the right side and left side?


The right side hose expands when I take the cap off the expansion tank, so appears the cap is not venting correctly. Also appears there is a small leak at the hose connection to the expansion tank...easy fix there.


The expansion tank was replaced three years ago, so not original.


Do I just need to get a new cap?


Thanks in advance.

 

It could be a bad pressure cap on the reservoir but when I changed all the hoses, water pump, t-stat etc mine did that because it was a pint or so low on coolant due to an air cavity. After bleeding by letting it idle with the cap off until the t-stat open then squeezing the upper hose the level dropped and added a pint or so and then no more problems.
Also the t-stat has an air bleed hole in its rim and it should be at the 12 oclock position and if its not it can cause the hose collapse also as any air in the system won't bleed back to the reservoir.


Dave

 

The reservoir cap has two functions the first is to allow coolant to flow into the overflow tank and the second it to allow the coolant to flow back to the reservoir. All of this activity takes place as the engine gets hot and then cold. When the car cools down and the valve in the cap does not work properly and does not allow the flow back into the engine a vacuum is created and then the hoses collapse and that is if everything is the way it should be.

When all is not the way it should be the system could have air in it or your hose is failing. I would first check for air in the system then check the reservoir cap. If the hoses are questionable replace them it is never a bad idea.

 

The low coolant light came on last night on drive home; opening the hood within a minute of stopping I saw the right upper radiator hose was collapsed.


I probably did not get all the air out of the system when I replaced the octopus hose last summer....and this hose was collapsing at that time as well. I was going to replace it but didn't....guess what I will be doing this weekend....

 

On many cars, one of the major radiator hoses has a wide coiled spring running through it to prevent collapsing (sorry - I've forgotten which hose that would be). In some cases, I've bought a replacement hose that didn't include the coil and had to swap in the old coil.

Is it possible that Lanny's hose is supposed to have a coil in it, and that it wasn't replaced with a new hose install sometime in the past?

Could someone give their right side (upper) hose a quick squeeze to check for the presence / absence of that coil? That hose is the only front hose I haven't replaced - this would be good to know.

 

Neither the 2 factory original upper/lower hoses or the replacements had coils in my '97.


Dave

 

No coils in my replacement hoses on my 03 or the ones I replaced. My upper hose from radiator was collapsing. I put on a new on and it stopped. As for bleeding the system, they are not hard to do at all, you really do nothing as the resivor tank is your high point. It bleeds there on its own as I am to understand, then add fluid as needed to top it off.
Perhaps you have a slow leak it.

 

With the engine at idle and the reservoir cap off I squeezed the right upper hose until it got too hot; had lots and lots of air come out. Wife droved to and from work, checked it last night and hose was good and so was coolant level.


Will still need to fix the small leak at the reservoir hose this weekend.
And I will keep checking it every night.
Thanks for all the help.