Ok guys I got a strange one.
1999 XK8, after driving awhile coolant spills out of overflow tank in fender. Low coolant light comes on. Gauge never shows hot or overheating. New water pump,thermostat, radiator flushed out, new cap, expansion tank, and new tstat housing (alum.).
If overflow tank is empty, coolant level correct in expansion tank, driving car bout 40 miles round town, the low coolant light will come on and coolant will spill from overflow in fender, cause its completely full. Once car stopped fans will run for about 1-3mins, with key off. Again no overheat and gauge shows normal the entire time.

Any ideas would be great. Thanks Guys.

 

I'll bet you installed the coolant reservoir hoses incorrectly and hooked the atmospheric catchment tank to the radiator air bleed line. THEY DO CROSS and that does not look right but it is the way they are routed!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I once had to cover for another mechanic (shop foreman) when the X308s were introduced and he swapped the lines after a coolant system repair. He was on his day off and the car came back for coolant leak!!! I found the lines reversed and corrected the problem. I topped up the system and told the customer that the system had an air pocket that required bleeding and sent them on their way. I never told anyone in the shop but I checked his coolant routing a few times after that and he did not repeat his screw-up. The customers usually don't care when the car is in warranty.

Even factory trained mechanics get it wrong sometimes (I hate it when it's me)!!!

bob gauff

 

I thought that too. But there is only one hose on the expansion tank which goes to the overflow in the fender. The other goes to the top of the tstat housing. So, two hoses total on the expansion tank.

 

I just re-read the post and saw that you are talking about an XK (not an XJ sedan)

Here is a TSB that was issued because of hose routing confusion on the XK8 models.

bob gauff

 

I cant open the bulletin. Too new of a user I think.

 

Was able to open bullentin, but does not apply to this car. Will keep it though thanks. Any other ideas?

 

Sticking thermostat will cause overtemp and pressure to force coolant out of the reservoir and into the atmospheric catchment tank. The guage may or may not show a slight overtemp situation as the gauge tends to stay in the middle until an extremely high temp occurs. You can monitor the actual engine temp with a handheld diagnostic scanner that has data monitoring capability. Water pump impellors are known to disintegrate and not pump coolant. Keep diagnosing.

Here are some more ideas.

bob gauff

 

thatguy, it does apply. Notice the ISSUE date from jaguar - 10/1997. The 1997s and 1998s were being sold, and you guessed it...1999s were next to roll off the line. They didn't make a new TSB after every model year and mention it by year (who knew when the xk series would end?) but this will still apply to all MY up to and including 2002

 

bob, endless lists of TSB documents on his computer! (I've seen em)

 

Not sure what you got going on but see if any of this helps http://www.gusglikas.com/AutoRepairCoolantTank.htm

 

I have the exact problem being discussed here on my 2000 XK8, the problem is it's not the original engine, and possibly not the original radiator either. I got the expansion tank salvage, the rear nipple is blocked making it the post 1998 expansion tank.

Coolant is being sent the atmospheric recovery tank in the wing when engine heats up and the coolant expands, but it's not being drawn back to the expansion tank when it cools. Some of it is drawn back, but not enough resulting in the recovery tank overflowing and low cool in the expansion tank.

I've been through the ringer trying to resolve this...new thermostat, thermostat housing, expansion tank, expansion tank cap, heater feed hose, it passed the block test for cracked block and blown head gasket. I think/hope I'm getting close thank you motorman and H2Oboy (these forums help me solve a lot of issues)

However I do have a question

Since I don't know what year my engine is and/or radiator, and the expansion tank rear nipple is blocked will it hurt anything to drill a hole in the rear nipple and connect the radiator hose?

Note, I currently have the radiator hose connected to the blank nipple and am having the coolant problem, could it be something else?

I'm at lose, I've the car to an independent whom I trust and used to work on my XJS and the dealership, still the problem exists..

 

I'm meant to add the system has also been pressure tested and holds pressure.

 

thatguy - What you described is exactly what I had in my 98 XK8. In my case, it was the head gasket that was the issue. It took several months and trips to determine the cause. In the end it was confirmed by two different shops.

After the repairs, my temp guage actually works! It used to go to the middle and just stay right in the middle. Since the repair, it varies between a quarter and halfway depending on traffic and speed.

If everything else you tried have failed, get a shop to check for exhaust gasses in the coolant. In my case, the engine did overheat at some point, but the repairs were made before a major catastrophy.