Our 1988 Landcruiser is overheating on long drives going over 100 km/h. it goes fine between 80 and 100 km/h. The local mechanic ]Morocco] suggests i take out the thermostat. We are heading into the desert so bit worried about overheating but also worried about taking out the thermostat:

Is this a good idea? Thanks

The thermostat could be the problem. Just take it out, and keep it with you. You can always put it back later. If the problem is not solved you have to fix the fan. Because the locking system, that works with a gel, is not working the fan often does not turn around fast enough. Fixing the fan is a simple job. Every mecanic can do it. I did it myself last time, and just put a lot of sand in the gel. It worked fine.

thats the viscous coupling your talking about, they commonly fail on mechanical fans as fitted to TLC and landrovers. You can check this by wearing a heavy glove and trying to stop the fan rotating, but this is highly dangerous unless you know what you are doing!!! In a crisis I believe you can weld the fan up so it will always travel at engine speed, but check this with a mechanic first as I have never tried it. It is relatively simple to replace if you can find a spare or get one sent to you, they are not too big so could probably be sent fairly cheaply.

make sure your rad is fully operating, sometimes areas of it can be blocked by debris, try flushing it through with a proprietry cleaner and then reverse flush it, but have some radweld to hand as it may then start leaking from a hole that was previosly blocked!

ensure your rad is clean, no grass seeds or dead insects!! don't jetwash it clean as this can bend the fins.

make sure your cylinder head gasket is ok as if this has failed it can cause overheating, check for oil in the water and water in the oil (a white deposit around the filler cap and dipstick)

If you are really struggling for cooling wedge the bonnet open a couple of inches and then ratchet strap it down

I have found in soft sand that using low ratio helps drop the temp as you can run at lower revs due to the increased gear options you have. On firmer sand you will be wanting to travel at higher speeds than this allows. If you over heat then as soon as you reach firm ground turn into wind and open the bonnet. avoid switching the engine off (unles you are also overheating whe stationary) as this will heat sink the engine, but if the temperature continues to rise you will have to just cross your fingers and turn it off. If it boils wait until it has cooled down before adding water, or add hot water, as otherwise you could crack the head.
remove any obstructions to the airflow such as spotlights, and if necessary the radiator grill, but replace it when you are on the road as it protects your rad from damage from flying stones etc.

one of the cruisers (an H60)on a recent rip I did persistently overheated due to a blocked rad in the desert at 50C. It was regularly up in the red but the engine survived, they are a pretty tough unit but I wouldn't reccoment this as a course of action!! my own H60 never gets more than 1/4 way up the gauge in the UK and in the desert rarely got above 1/2 so if yours is overheating I think you have significantly reduced cooloing system efficiency

hope that helps,

Andy
TLC H60
101 Landie Ambie
1968 morris minor traveller
Author of Me dad and the Plymouth to Dakar
http://stores.ebay.co.uk/Captain-Mog...3aFQ3aSTQQtZkm

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1990 Landcruiser H60. Full rebuild completed 2014

Hi,

Yes!
Maybe the problem is in the thermostat (you can test it submerging it in hot water and seeing if it opens in the designated temperature - 90º???). If not, you will not miss it in the desert except in cold mornings when the engine will take a bit longer to warm up.

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Regards,

NCR
Lisboa, Portugal
http://ncr2006.blogspot.com/

thanks for your replies. i will take on your suggestions. I had a look at the manual _ covers all Land Cruisers from 1980 to 1990). it says; caution - never drive whithout the thermostat, are they being over cautious?

Hi,

The thermostat ONLY function is to allow the engine to reach it's working temperature faster (it allows the cooling liquid to flow through the radiator only when it reaches a certain temperature). This "working temperature" is the temperature where engine wear is smaller.
If you don't have a thermostat that period will be longer and engine wear increased. In hot climates the thermostat is almost irrelevant as the engine will reach normal temperature very fast.
Just warm up the engine in the morning and forget about it until you return.

__________________
Regards,

NCR
Lisboa, Portugal
http://ncr2006.blogspot.com/

Well, they are right. It's there for a purpose, so rather than removing it altogether it's reasonable to have it checked and replaced if it's found faulty. That is, if you have access to spare parts. If not, you could try removing it for a while to see what happens. You can't overheat the engine because of a missing thermostat.

A faulty thermostat makes the engine run too hot because it opens up too late or not at all.

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Roman (UK)

Now I'm curious...what do you think could happen, Roman?



PS: I believe this discussion should be here:
http://www.horizonsunlimited.com/hub...overland-tech/

__________________
Regards,

NCR
Lisboa, Portugal
http://ncr2006.blogspot.com/

If you are doing this use the hand throttle to get the revs to about 1000rpm to ensure the oil pump is correctly lubricating the engine, at tick over on many cars the oil pump is inefficient, don't know if this applies to landcruisers, someone else might, but I always do this if I am leaving the engine ticking over for a while to be on the safe side, just in your case make sure it doesn't overheat!!
As far as I am aware the only problems with removing the thermostat are as above, but the warning in the book was enough to persuade me not to do it, although we had the luxury of usually being able to drive round the problem so it wasn't too dire an emergency.

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1990 Landcruiser H60. Full rebuild completed 2014

On arrival in Africa, we remove the thermostats as a matter of course - it's never led to any noticeable problems.

You want to have the engine 'up to speed' each morning, before you hit the dunes though. Try it with a cold engine and the lower power available is dramatic.

Sam.

Hello NCR,

It could unblock the passage of engine coolant (if the thermostat is faulty), but haven't you explained it yourself already?

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Roman (UK)

Hi Roman,

Yep, I believe I did.
I thought you were talking of consequences besides unblocking the passage of engine coolant.

__________________
Regards,

NCR
Lisboa, Portugal
http://ncr2006.blogspot.com/

The reason it says that is in many cases the thermostat when open also slows down the water circulation and gives the water more time in the radiator to cool off. In therory taking out a thermostat could lead to overheating since the coolant does not have enough time to cool in the radiator before being recirculated. Saying all that I have puled out a thermostat before and never had a problem other than slow to warm up.

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John

I just and only talk out of experience, but when we had serious overheating problems in very hot places in hard conditions, the problem has quite solved simply removing the thermostat. However, the old rad did not help to make things easy. In the other hand, an additional electric fan was very helpful, but hard on the alternator. We also changed the 20 -40 (or whattever it was) to straight 40, used by the locals.

As mention before, be very careful as serious overheating may shoot off your rad hoses anytime, spraying steam and very hot water, dangerous if the bonnet is open.

Good luck. And keep us inform, if you can.

why? if your cooling system is in good order you shouldn't need to remove the thermostat, assuming it's a landy or 'cruiser. If it does overheat then is that either a cooling system or driver issue? the only time my 'cruiser got hot was in soft sand with an inexperienced driver. the other one had a bad radiator, but the skill of the other driver was able to work around the problem and the vehicle survived. That was in 50C. likewise there should be no need to fit extra fans to vehicles like these. if you feel the need then there are probably other issues (as above) which need to be addressed first.

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1990 Landcruiser H60. Full rebuild completed 2014