Overheating TD5

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Futureboy

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Hi all!

1st post so please go easy! :)
I bought a 99 TD5 Auto a few weeks ago and it's been running great (and i'm enjoying tidying it up)
The engine temperature has always sat around midway on the dial when it's warmed up until today!
It was running slightly above the midway point, then when i drove up a hill it gradually climbed until just over the 3/4 point and i appeared to loose power. When the road leveled out, the temp dropped and power appeared normal.

Any ideas.........??? For what it's worth, it's relatively low milage (56,000) and appears to have lead a decent life!

Cheers in advance, Steve
 
Dare i say head gasket gone?, mine heated up and cool down and lost power (limp home mode) before i found out H/gasket had blown.

Are you loseing water, check levels, is oil creamy white, have a sniff test done and this will tell you if h/g is gone.
 
Is it only on hills, or generally when under more load?

Could well be the waterpump giving up the ghost, and ofcourse head gasket as already mentioned. The first could lead to the second.

Always worth checking that the thermostat is functioning properly too. Whip the 'stat off and dunk it in a bowl of water around 95 degrees. The thermostat is affectively a ball of wax that melts at around the temperature and opens a valve allowing coolant through to the radiator... if it is working, you should see it open up in the water at about 90 - 95 degrees.
 
Matt TDi said:
Is it only on hills, or generally when under more load?

Could well be the waterpump giving up the ghost, and ofcourse head gasket as already mentioned. The first could lead to the second.

Always worth checking that the thermostat is functioning properly too. Whip the 'stat off and dunk it in a bowl of water around 95 degrees. The thermostat is affectively a ball of wax that melts at around the temperature and opens a valve allowing coolant through to the radiator... if it is working, you should see it open up in the water at about 90 - 95 degrees.
Click to expand...

TD5's run a completely different cooling system to a standard vehicle. You need to understand how the cooling system works in order to find the fault.

A standard vehicle pushes the coolant around the system. As pointed out above, if the thermostat jams closed it will lead to overheating.

On a TD5 the waterpump SUCKS the coolant around the system. It has a twin valve thermostat. The first valve opens as a traditional thermostat would when the coolant reaches the required temp. (It starts opening at 82degs and is fully open at 96degs C). The second valve (known as the bypass valve) opens when the engine revs exceed 1500rpm.

The suction of the engine at 1500rpm pulls the thermostat open. If there is a loss of suction this valve will not open and can result in loss of power. Check the expansion tank cap, waterpump and thermostat.

The 'normal' operating temp of a TD5 is so wide in comparison to other engines that the temp guage on the dash will not move from the 'normal' (upright) position when the temp ranges from 82-96degs. My own TD5 also eats coolant temp sensors. These will often not show up as failed on a diagnostic but will also give the loss of power symptoms you describe.

96 degs is extremely close to the blowing up point of most cars so landrover have got the TD5 operating temp right on the limit.

If there are no obvious sisns of any leaks I would try changing the temp sensor first.

The coolant parts on a TD5 are NOT expensive if you wish to change parts to eliminate them.

temp sensor £16
expansion cap £4-£8
Themostat £15
waterpump £25

here is a piccy of a td5 thermostat. The bit coming out on the angle is the bypass valve.
PEM100990.jpg
 
ratty said:
coolant.
Click to expand...

Depends how you mean by close really.

On most cars and trucks the danger zone is regarded as coolant temp over 105 degrees. That's not the ideal running temperature, but what I was taught to regard as the danger zone.

I would agree though that it's getting close to the line at 96 degrees. I'm quite surprised to hear that of the TD5. Most thermostats I've come across are usually fully open at 94 degrees coolant temperature.
 
Matt TDi said:
Depends how you mean by close really.

On most cars and trucks the danger zone is regarded as coolant temp over 105 degrees. That's not the ideal running temperature, but what I was taught to regard as the danger zone.

I would agree though that it's getting close to the line at 96 degrees. I'm quite surprised to hear that of the TD5. Most thermostats I've come across are usually fully open at 94 degrees coolant temperature.
Click to expand...

Yep. It took me along time to get my head around it too. There aren't many cars where the temp gauge won't move a mm through a coolant range of 16 degs either. (especially not when the temp is that high).

I run with my TD5 with my diagnostic plugged in when I can. I just don't trust the temp gauge cos of the massive tolerence it has in the 'normal' temp range. I can see why fitting a black box to a TD5 is such a good idea.
 
Hmmm.......... the more I read threads like this one the more I think my head gasket is blowing:

My water pump, expansion tank cap, top hose and thermostat have all been replaced. The expansion tank overflow still spits fluid out. The top rad hose is also often rock hard as if over pressured.

When under heavy load (either on long uphill motorway stretches or when pulling a heavy trailer) the temperature gauge goes up and the car goes in to limp mode. This doesn't seem to happen every time though. If I wait for the engine to cool a bit things return to normal.

The car has been sniff tested and dip tested a couple of times and the garage assure me there is no sign of fuel or oil etc. in the coolant.

I'm about at the stage where I will just try and change the head gasket to see if it solves the problem.

Any good tips? - Do I have to remove the bonnet as it says in Rave for example and can I tell which hole gasket to get before I've removed the old one?
 
Sorry Future Boy - I hijacked your thread a bit there - welcome to Landyzone; have you checked for the obvious things like coolant level and leaks etc? As the others have said there's a few cheap fixes to eliminate things like the exansion tank cap.
 
Headtester said:
Hmmm.......... the more I read threads like this one the more I think my head gasket is blowing:

My water pump, expansion tank cap, top hose and thermostat have all been replaced. The expansion tank overflow still spits fluid out. The top rad hose is also often rock hard as if over pressured.

When under heavy load (either on long uphill motorway stretches or when pulling a heavy trailer) the temperature gauge goes up and the car goes in to limp mode. This doesn't seem to happen every time though. If I wait for the engine to cool a bit things return to normal.

The car has been sniff tested and dip tested a couple of times and the garage assure me there is no sign of fuel or oil etc. in the coolant.

I'm about at the stage where I will just try and change the head gasket to see if it solves the problem.

Any good tips? - Do I have to remove the bonnet as it says in Rave for example and can I tell which hole gasket to get before I've removed the old one?
Click to expand...

Overpressurisation is the only fault I had with my TD5 when i got fecked off with it and had the headgasket changed wether it needed it or not. It turned out to be the right decision. Mine had the nylon dowels and they were allowing the head to shift.

I have found that many of the coolant parts I have had to replace more than once. 2 top hoses, 2 radiator caps, 3 temp senders, 2 thermostats. Don't rule out parts just cos they are new.

My landy also came up clear in 3 sniff tests and 3 pressure tests. It was only cos I got so fecked off with it happening I had the head off.

Overpresssurisation was the only symptom on mine too. I decided it must be the head after loosening the bleed screw on the top hose and then watching an occasional bubble pop out. If I increased the engine revs the bubble would pop out a bit sooner. That was my only hint.
 
Cheers Ratty, I'm heading down the same path as you I think - sounds like a new head gasket to me!

Do I really need to remove the bonnet to change the gasket?
 
I had the same symptoms and it was the head gasket (LR dealer pressure tested and said it was OK, but it wasn't). Don't let it overheat again as this could help the head to crack = expensive. Use metal dowels and new bolts when replacing the head. Also, there are different thicknesses of gasket. Look on the old one and you'll see a code (I think it's a number of small holes). Replacement must be same thickness. LR say the head can't be skimmed, although some on here have had it done. If you do skim it you'll need to adjust the gasket thickness.
 
Thanks Pastmaster, I'm plucking up courage to have a go at this which could be a bit of a challenge to my spannering skills (or lack of them) - would you get genuine LR parts or go elsewhere?
 
Headtester said:
Thanks Andy - keep the tips coming guys I'm still wary of attempting this!

thanks
Click to expand...

See how much your local engineering firm will charge for doing it. I decided to get my head skimmed too. Skimming heads down my way is bloody expensive (£100). It's half that in most places. I had a chat with the local engineering company and they agreed to do the whole job for about £450. At that price (with a years warranty) it was stupid to do mine myself. The price also included fitting the egr blanking kit which was a good move cos one of the bolts needed drilling out.
 
Cheers for all the advice folks.
I gave the car a quick check last night. The oil is fine, but it seems at though i have a coolant leak somewhere............just need to find out where!!!
After reading this thread, i might think about getting the gasket done anyway as i intend keeping the car for a while.

Steve
 
Futureboy said:
Cheers for all the advice folks.
I gave the car a quick check last night. The oil is fine, but it seems at though i have a coolant leak somewhere............just need to find out where!!!
After reading this thread, i might think about getting the gasket done anyway as i intend keeping the car for a while.

Steve
Click to expand...

If you pop down to your local garage they should be able to pressure test the coolant system. Basically you pump the coolant systen up with air to replicate the pressure of the engine at running temp and under load. This means you can get your head and fingers in all the places that you can't do with a hot or running engine.

Check around the expansion tank for signs of a leak after a run. If the cap is blowing under pressure or is faulty there should be some moisture there.
 
Futureboy said:
Cheers for all the advice folks.
I gave the car a quick check last night. The oil is fine, but it seems at though i have a coolant leak somewhere............just need to find out where!!!
After reading this thread, i might think about getting the gasket done anyway as i intend keeping the car for a while.

Steve
Click to expand...
Coolant could be leaking because blown gasket is pressurising the system. It's can also be (sorry:eek:) a sign of a cracked head. In which case you'll eventually get white smoke out of the exhaust. Hope it's not that, but they do crack... If you're just replacing the gasket might as well get Genuine parts - they're not that pricey. If it's the head, there's a reinforced replacement around which has featured in previous threads. If you're taking the head off it's worth getting it tested for cracks anyway. The reason LR say don't skim is apparently because the surface is specially hardened. But various people on here have had it done.
 
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