90 series losing coolant

[ric]

Hi,
I am new to this site, but i could do with a bit of advice.

My [FONT=Verdana, Arial, Helvetica, sans-serif]1999 deisel colorado is losing about a litre of coolant in only 30 miles!! no obvious leaks. There has been losses for a few years, but not on this scale. A previous post mentioned rear heaters may leak. any clues wold be helpful.
Also timing belt change is due. Is it recommended to change hydraulic tensioner and or water pump as well (180000mls on clock) belt changed 55000 miles ago (5.5years))

cheers[/FONT]

 

[Graham]

A liter of coolant every 30 miles

If it's the rear heater, then I feel coolant would be sloshing around in the rear foot area, and all your windows would be well and truly steaming up.
Is there much wet in the rear?

Gra.

 

[Andrew T]

if you have no coolant leaks under the car or inside the car, a litre is quite hard to hide,

I would suggest you check your oil level and get a compression check done to see if it is the head gasket has gone to see if the water is either going into the oil or out the exhaust pipe.

 

[AndyCook]

rear heater pipes run under the floorpan of the car - park somewhere dry (not easy at moment i know) and run engine, with rear heater set to max heat and see if there is a leak under car - look for the metal heater pipes
they are know to rust

 

[chadr]

Hi Ric,

Is yours a automatic ? If so, check the gearbox oil for contamination. The ATF cooler sits inside the radiator and can leak causing the ATF and coolant to mix. You will find a few threads on here on this subject. It's not good news if that is the case - I'm afraid.

The rear heater pipes usually corrode before the rear heater matrix itself, so check the pipes themselves. They run from the engine bay alongside the chassis rail on the driver's side and then into the rear passenger compartment.- they will similar to brake pipes in size/diameter. Mine started leaking very slowly and were so corroded that they simply crumbled to the touch. I just blocked them off inside the engine bay, though it is not difficult to replace them with rubber heater hose.

Let us know how you get on....