Hi all.
I have a 2003 L200 and just lately it has started to overheat when i drive up hills. It runs seemingly at normal temperature until i start to go up fairly steep hills. the temperature then rockets to the red and once it dumped the water from the radiator. I had it looked at by a garage and they could find nothing wrong. They ran it for several hours, driving it, idling it, did system pressure tests and trying to replicate the problem but found nothing wrong. I have been driving it for a few days and it's been fine, until i had to drive up a steep hill and it overheated again! It's very annoying and very inconvenient. I've had the truck for 5 years and it's never done this before. Anyone out there ever come across this before and have any clues as to what it might be please?
Thanks in advance.

Hi Tiger, have you removed the EGR. When was the last time you flushed the radiator and renewed the coolant. Could be a sticky thermo, If you flushed the system recently could be an air lock.

When you switch off the engine is the expansion tank bubbling after its got up to temperature ? before we go down the failed head gasket route

^^^^^ what he says!

No. I haven't removed the EGR and not flushed the system. It dumped the coolant so it was re-filled by the AA and again by my garage when it first happened a few weeks ago so I hope they checked for air locks. I've been keeping an eye on the levels daily and it has maintained it well. I have not had to refill any water. And yes, the expansion tank does bubble when it's hot. I have also found that if i stop accelerating it quickly drops temperature again. I drove 220 miles today and it only went really hot when i went up three steep hills. As soon as i crested the hill the temperature dropped again. The rest of the journey it was absolutely fine, although my nerves weren't!

If the expansion tank is bubbling it is either a porous egr cooler ( water can be made to bypass as a temp measure to see if it's that) or unfortunately headgasket failure....as for header tank to bubble you are getting exhaust gases in the water

I would consider removing the EGR and cooler as it may have become porous. i would tend to stop driving it until it has been resolved as if you havnt got HGF now you are tempting feight

OK. Thank you both. I will call my garage tomorrow and let them know what you have suggested and see what can be done. I will not use the car now until it is fixed. Can't afford to screw it up! Love it too much.
Thanks again for the advice.

you could join the site in full and have acess to the tech section and do it yourself simples with the instrctions on here and you know it has been done right

where you from Tiger1?

hi did you find out what was causing it to overheat? I'm having the same problem going up steep hills, but runs fine otherwise. Ive replaced water pump and thermostat but still have the same problem.

Nuttychester
9 times out of 10 overheating is head gasket failure
try changing the rad cap , water pump, flushing the radiator , cleaning the fins, removing the EGR valve and cooler and checking you've not got an air lock in the system
after you've done all these relatively inexpensive not overly complicated things to try and cure the overheating you'll end up with only the head gasket left as a culprit
bubbles in the radiator ..... head gasket
bubbles in the overflow tank ....... head gasket
oil in the water ....... head gasket
water in the oil ....... head gasket
bubbles are common signs
oil and water mixing are less common signs

assuming you got a classic (K74 from circa 97 to 06 ish) then engine should get to temp quickly within a mile or 2 then sit at exactly half way
if the temp gauge goes up you've got issues you need to sort out for sure

My guess would be either blocked radiator or possibly failing viscous fan. Mine overheated on hills only and was the radiator needed flushing through, when headgasket went it threw the lot out of the header tank and sent the heater gauge into the red...but krutly does have a comprehensive list there to be advised by!