coolant loss

[thomas 75 connie]

Hi my dad has a 99 2.5 v6 75 and is putting in 2 litres of water/coolant in the tank every 4 days or 50 miles we took the cover off to see if some had leaked into the v but its bonedry. If the thermostat is gone ie cracked can we look at this without taking off the inlet manifold. The temp guage has gone up a couple of times but it went from normal to red in 1 second then back to normal straight away ie seemed to bounce any help would be much appreciated thanks Thomas

[kaiser]

Have you checked for external leaks?
Have you got mayonnaise under the oil filler cap on a hot engine?

[Scribbler.]

:lol: Hi there Thomas, first my 75 KV6 also jumped into the red then back to normal several times before I changed the header-tank cap, a new one is around £11. Get the correct pressure, (mine's 100.lbs. psi.) DO NOT entertain Head Gasket Failure until and unless you have the cylinder pressures checked first; (about £40.) Once they're all confirmed ok check for leaks until you find the coolant leakage.
A colourizer die may help with this or, temporarily, add some "K-seal" which turns pink and is easier to spot leakages. Good luck my friend. Mike. :lol:

[stocktake]

Hi Thomas,

Have you checked / replaced the header tank cap? as commented above? Common problem. next is the T/Stat housing.

You also need to check your fan is working on the KV6 it is very important.

Temp guage will only go to red when it has actually overheated, not very good the temp guage.

[FredSpencer]

Originally Posted by Scribbler.

:lol:Get the correct pressure, (mine's 100.lbs. psi.)

Isn't the current advice to switch to the 140psi caps?

[JohnDotCom]

They are now only available in one rating if Genuine OEM, unless your Serial Number is Below No: 158719.
Normal Part No. From Serial No: 158719: ESR1480 Cap-expansion tank pressure £10.97 + VAT
Early cap up to Serial No: 158718 Part No: PCD000080 Cap-expansion tank pressure £11.46 + VAT
Don't use Copy Part ones.
Available from Rimmers and all XPart Parts dealers.

[FredSpencer]

Originally Posted by JohnDotCom

They are now only available in one rating if Genuine OEM.
Part No: ESR1480 Cap-expansion tank pressure £10.97 + VAT
Don't use Copy Part ones.
Available from Rimmers and all XPart Parts dealers.

The one I replaced is a 140, as was the one I borrowed from stocktake for a few days, so I got a new 140 from Evans Halshaw in Leeds who are an XParts dealer. Their man did say the 100 was the one to get but I got the 140 on the strength of other threads on here. I seem to remember it was something to do with BMW not being happy with the old one.

[thomas 75 connie]

Hi thanks people there is no mayonnaise in the oil and she runs to smoothly aswell ill get my dad to change the cap to see if that does anything.
Also about the fan yes that works fine, the fan starts after approx 5 minutes of starting the car sometimed even less.Thanks for everybodies input i may not post alot on here but im looking quite alot id love a 75 for myself but the insurance is to prohibitive at my age i spose ill just have to keep driving round my old mg montego thanks again Thomas

[stocktake]

Hi Thomas, the fan check :

Start car from cold.
Select Lo on air con setting on both drivers and passengers side.
Make sure Econ is not showing

Fan should run.

[SD1too]

Originally Posted by FredSpencer

Isn't the current advice to switch to the 140psi caps?

Guys, you've gone mad with your units! MG Rover says that the KV6 expansion tank cap is rated at 14.5 psi.

Also, Thomas, your engine cooling fan running five minutes after starting the car is not an indication that all is well. If the air conditioning is off and the ambient temperature is cool and your road speed is not low or zero, I would not expect the fan to run at all. You may have suffered the loss of low and medium fan speeds; a common fault. I suggest that you carry out Stocktake's test and report back. If you're losing 2 litres of water, something is definitely amiss.

Simon.