overheating light and loss of power

hi all, havent been on here for a while, looking for some help with my grandads freelander its a 53reg td4 diesel. just rang me up and explained that the overheating light has recently started coming on and the engine loses power, he says there is coolant etc, any ideas?

commercialmatt said:

hi all, havent been on here for a while, looking for some help with my grandads freelander its a 53reg td4 diesel. just rang me up and explained that the overheating light has recently started coming on and the engine loses power, he says there is coolant etc, any ideas?

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firstly check the coolant, it may need changing if its been in for a long while.

i changed the coolant less than six months ago, just after christmas i think.

just a quick update i've been over and had a look, theres plenty of coolant, oil is fine engine starts and runs fine. went out for a spin temp rose to about half way which is normal aparently, drove about 5 miles fairly steadily and the temp gauge went right up at once, then down to about 3/4 and back up to the top then the red light came on and the car wouldnt go above 30ish.
would i be right in saying that some kind of limp home thing was turned on when the temp went up? we pulled over in a layby and i had a look at the engine and the coolant was up as you'd expect (and no bubbles or anything) and the fans were working, the engine felt very cool. i suggested putting a diagnostics jobby on it do you think this would help?

You may have a faulty thermostat if the coolant appears fine when it is overheating.

mmmm hadnt thought of that! any ways to simply work out if its that?

just a thought, there is hot water goin through the pipes on the radiator, so the thermostat may be working right?

Have you checked the ancillary drive belt????

wouldnt this be aparant straight away? i dont have much experience of freelanders!

commercialmatt said:

wouldnt this be aparant straight away? i dont have much experience of freelanders!

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Well it drives the water pump for one and you mentioned a red light came on, it drives the alternator too so got to be worth a look.

where is the belt on a freelander? the red light was on the temp gauge tho i'd say the alternater is fine

commercialmatt said:

where is the belt on a freelander? the red light was on the temp gauge tho i'd say the alternater is fine

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Look underneath on the drivers side infront of the oil filter next to the sump.

I think I am correct in saying that a TD4 thermostat is a twin valve suction operated thermostat the same as is found in a TD5. A knackered radiator cap, jamming thermostat valve, loose or snapped fan/ancillary belt or knackered or weak water pump will all give the symptoms you describe.

A traditional thermsotat opens when the temp reaches the desired level. The thermostat on a TD4 and TD5 has one valve that opens at the correct temp, and another is sucked open by the pressure from the waterpump when the revs exceed approx 1500rpm. Any of the above can cause loss of suction/flow so therefore loss of coolant circulation.

howardo said:

Look underneath on the drivers side infront of the oil filter next to the sump.

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Sorry, am wrong i was thinking of the l-series diesel.

thanks all for your help, he's opted to change the thermostat, any advice on this? is it easy ive had a look and it doesnt seem too bad, maybe a little tight! found them online for about £30 this about the right money?

Probably worth changing it, I don't know if it's the same as the petrol ones, but they are a common failure point.