200tdi heating/cooling system

I have posted a couple of threads on here related to the above problem.
I have changed the thermostat three times. I have changed the sender unit twice. I have removed the visco's fan and put a kenlowe electric one on. I have flushed the heater matrics out. I have had the top nut off the rad to try and ensure the system is properly bleed and there are no airlocks.
The heating system is still luck warm. I have to drive a good ten to fifteen miles before the temperature gauge moves off from the bottom. The gauge moves about half way then drops down to almost the bottom then gradually moves back up slowly after a few more miles. Every now and again it drops back down again.
Has anyone else had this problem? I'm now thinking of changing the water pump to see if that makes any difference as I am running out of ideas.
There are no leaks, the system does not appear to pressurise much. I can run it and remove the cap after a run without any problems. I don't have to refill the anti freeze. Any suggestions?

maybee its a waterpump failure but that would cause it to overheat.have you tried covering the radiator with a rug so it gets hotter?

the 200tdi was allways a cold running engine anyway.

MoorlandBOB said:

maybee its a waterpump failure but that would cause it to overheat.have you tried covering the radiator with a rug so it gets hotter?

the 200tdi was allways a cold running engine anyway.

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I forgot to mention I tried a rad muff which had no effect at all, I also tried a piece of linoleum in front of the rad.
During the summer I drove down to Montpellier in the south of France. It was 35c degrees and I had removed the visco fan and hadn't yet fitted the Kenlowe electric. I got there and back without any problems. Only once did it edge towards the red whilst I was going up a long steady hill for several miles.

I'm only thinking water pump as that's the only thing I haven't tried. On a normal car yes it would over heat but on this I don't know what to expect.

Are you sure your gauge isn't broken or the break.?!

What is the ground like between chassis and engine plus engine and bulkhead? The temperature gauge works on the basis of resistance to ground so if the ground isn't perfect the gauge will read low. It takes 30 minutes to fit a stonking earth strap from the chassis to the engine and on from the engine to the bulkhead. I did the same last week due to iffy cold starting and the whole thing runs so much better plus the gauges are more stable.

Had mine ticking over for a good 15 mins yesterday, rad covered, did not get particularly warm although the temp gauge was reading, albeit low.
Guess it is a fairly cool running motor, won't really know until I get the thing back together and drive it.

potus said:

Had mine ticking over for a good 15 mins yesterday, rad covered, did not get particularly warm although the temp gauge was reading, albeit low.
Guess it is a fairly cool running motor, won't really know until I get the thing back together and drive it.

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You don't mind that at all other than it being more efficient when warm and being able to blow warm air out of the heater

I'm removing the viscous fan and going electric in an attempt to get some heat into it. If that doesn't work I'm swapping the radiator and intercooler round << Joke.

cowasaki said:

You don't mind that at all other than it being more efficient when warm and being able to blow warm air out of the heater

I'm removing the viscous fan and going electric in an attempt to get some heat into it. If that doesn't work I'm swapping the radiator and intercooler round << Joke.

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I have removed the visco and replaced it with a Kenlowe electric. I have had the Kenlowe on for three years now. I have heard it come on about three times in that period. Hasn't made any difference to my heating the cab problem.

cowasaki said:

What is the ground like between chassis and engine plus engine and bulkhead? The temperature gauge works on the basis of resistance to ground so if the ground isn't perfect the gauge will read low. It takes 30 minutes to fit a stonking earth strap from the chassis to the engine and on from the engine to the bulkhead. I did the same last week due to iffy cold starting and the whole thing runs so much better plus the gauges are more stable.

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I will check the ground connections but I don't think that is the problem. In the summer once the gauge is up it stays. Plus the heat or lack of heat coming through wouldn't be effected by the ground connection.

mikescuba said:

I will check the ground connections but I don't think that is the problem. In the summer once the gauge is up it stays. Plus the heat or lack of heat coming through wouldn't be effected by the ground connection.

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I know, but there may be multiple issues such as a poor ground and a dodgy hot air pipe connection.

Once the electric fan is on I'm going to try a muffler too. Next step was to check that the thermostat isn't jammed open. I'm changing my matrix too then in spring when I can afford to I'm fitting a diesel heater.

cowasaki said:

I know, but there may be multiple issues such as a poor ground and a dodgy hot air pipe connection.

Once the electric fan is on I'm going to try a muffler too. Next step was to check that the thermostat isn't jammed open. I'm changing my matrix too then in spring when I can afford to I'm fitting a diesel heater.

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I flushed out my Heater matrix, didn't see anything wrong there. Don't bother buying a rad muff they are useless. I have one. I found a piece of linoleum in front of the rad works just as well if not a bit better. I think a diesel heater is the way to go but they are about a grand. I have one in a van I drive, they are great if you don't mind spending that sort of money.

mt 200 tdi heats up fine......engine is normal temp and the heater is hot enough for winter after 10 mins or so...

cowasaki said:

I know, but there may be multiple issues such as a poor ground and a dodgy hot air pipe connection.

Once the electric fan is on I'm going to try a muffler too. Next step was to check that the thermostat isn't jammed open. I'm changing my matrix too then in spring when I can afford to I'm fitting a diesel heater.

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My Defender 200tdi takes about 5 miles to warm up but when it does it stays toasty, have to turn blower off sometimes or take coat off.
I have no fan at all and even towing a car on a trailer up the three mile hill over the Pennines yesterday, the gauge remained steady and didn't move up any at all.

Blanking the rad doesn't speed up the warming process much on mine, I have a new thermostat and always fill the rad via the brass plug then top up the header tank to avoid airlocks.

MoorlandBOB said:

mt 200 tdi heats up fine......engine is normal temp and the heater is hot enough for winter after 10 mins or so...

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Nice to know they can work, but I'm buggered if I can see whats wrong with mine. Mine needs a good twenty minutes before it even moves on the gauge. And I have changed three thermostats.

I notice you live in the alps. It's possible that it's simply much colder where you are for much of the year than the vehicles yours is being compared to. It was snowing/freezing in Chamonix in September (I was on my summer hols!)
The gauge movement sounds as though the thermostat is opening and closing as it should. As a simple test, with the thermostat open, you should be just able to keep your hand on the top rad hose - it should get up to around 80 degrees. If this hose is hot, then the water in the heater matrix is hot too. I wonder if there's a problem with the matrix? I know you have flushed it, but if a section of it is blocked, it will flush, but not transfer heat properly.

zeaphod said:

I notice you live in the alps. It's possible that it's simply much colder where you are for much of the year than the vehicles yours is being compared to. It was snowing/freezing in Chamonix in September (I was on my summer hols!)
The gauge movement sounds as though the thermostat is opening and closing as it should. As a simple test, with the thermostat open, you should be just able to keep your hand on the top rad hose - it should get up to around 80 degrees. If this hose is hot, then the water in the heater matrix is hot too. I wonder if there's a problem with the matrix? I know you have flushed it, but if a section of it is blocked, it will flush, but not transfer heat properly.

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I was thinking of changing it as they are not expensive, I saw someone posted on here that there's was working well until they fitted a Britpart matrix. Then the heating system didn't work so well. Then someone else came on here here and said theirs was fine.

oil cooler thermostat?? (Im presuming the 200 has one, the 300 does.)
Not somthing that fails regularly, but its there, if the oils been cooled all the time it would take and age to warm up.

On my 200TDi conversion I needed to rewire the temp gauge direct to the sender from the gauge. Original wiring passes through bulkhead and is joined by bullet connector, poor connection on mine. (Do a search on temp gauges reading wrong). Confirmed it was reading ok after finding the correct sender unit. Double checked the earthing, that was ok. Then looked at the heater unit. Hot water pipe carrying heater water was fine - about 80deg after a 5 min drive. (Replaced thermostat first, none fitted originally). Also check rad cap to see if that is working as it should.
Put blower motor on 2 speed and feel round heater unit under bonnet for air leaks escaping around the water pipes inlet mainly due to original insulating foam perished and missing. Quick spray with expanding foam, not too much, only want to seal the input area. Now cabin has lots of hot air, not quite enough to overcome all the draughts from missing door bottom seals but that's another story. It's amazing how much of the hot air wasn't actually making it to the cabin and warming the engine compartment instead. Worth a check, stuff some foam rubber in any gaps if you don't want to use expanding foam. It will make a big difference. I also made and replaced the foam gasket that fills the gap between the heater unit and the air inlet vent to the outside world to complete the job. The windscreen demists well and the heater is often turned down to a trickle as it gets too warm at slow speeds.(Less draughts) My viscous fan turns but doesn't really do anything, I have a Kenlowe but never use it. Hope this helps, you can fix it!

timtheenchanteruk said:

oil cooler thermostat?? (Im presuming the 200 has one, the 300 does.)
Not somthing that fails regularly, but its there, if the oils been cooled all the time it would take and age to warm up.

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That's an excellent point

Would you know if the 300 oil filter housing will fit the 200, I'm assuming here that the thermostat is in the housing, may be wrong

AND...I'm blanking off the rad in the wrong place, need to blank the oil cooler

Couldn't tell you, there's an exploded diagram on the web, the stat is in the "out" pipe outlet on the housing, the bottom cooler pipe iirc