03 M62 4.4 Vogue with fluctuating temperature.

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spud101

spud101

Member
Posts
88
Morning all.

My temperature gauge seems to have a life of its own, I'm not losing any coolant, the oil's nothing but oil coloured and there's no 'cream' in the cap / dipstick. The pipes aren't too soft or too hard (not that I've got a gauge in my arm but you know what I mean!) and I've just ordered an infrared laser thermometer so I can see what actual temperature the coolant it.

I've had a few 'coolant temperature' warnings but the temperature then goes down again (on the dial) and it all too often drops straight down to half way as soon as I start moving. (The electric fans are working (including when key is removed as it should) and the pulley one seems ok.

Any ideas? Thermostat?

(I've done the old trick of turning on the heater full blast and it does get hot, it takes a little while but then again I've had the air con on and it takes a little while to go from freezing cold to red hot.)

I'm thinking of doing the stat, flushing the rad and the refilling the system with fresh coolant whilst praying it's not the head gasket.

Does that sound right? I've not had her more than 6 months and I know they're like a good woman and need care and attend (and money) to keep them happy! :) (Although I primarily bought her as I wanted a big caravan and there's no better bus to tow a caravan than full fat Range Rover! :)
 
Thank you. I've got to admit I've always had a thing for Range Rovers and I was actually looking at a Discovery initially but when I saw how 'reasonable' Range Rovers were I had to have one. (I'm so not into buying a car on finance only to see it lose thousands every year, I'm a mechanics son and I know that cars are tools to help you get where you want. It's just nice to get there in a comfort!! I've also always had 'big' cars as the engines don't get too tired. My last 7 series had 175 thousand miles on her and she still jumped when you poked her with a stick. (Then again she wallowed like a fat bird in a dingy!) I can't imagine having a 15 year old 1.6 with that many miles on it being as good.

:)
 
Here's an update.

I was taking the pooches for a walk this morning and checked the coolant level (as I'm doing every day), she was parked on a slight incline but when I squeezed the top pipe to the rad there was lots of burbling coming from the cooling system (I've got to admit I was waiting for her to drop it all over the garage floor!! :eek: ) but it gurgled and bubbled for quite some time.

When it finished there was still plenty of coolant in the header tank but judging by the noises I thought a good few litres had gone somewhere. In any case, I've got some water in the back just in case she needs a top up and I went out with the dogs.

The temperature dial stayed mostly in the middle once warm but I got caught in some traffic by the A13 / A406 and it again started creeping up (nothing to severe) so I ramped up the heater and it blew red hot straight away, by then we were off and everything got back to normal. (I've got admit I was a little gutted as I thought I'd had a breakthrough.)


Anywho, I walked the pooches and when I got back to the car it was scorching so I put the air con on and drove back home, I got caught in some horrendous traffic but the dial didn't move a bit and it got me thinking. When the A/C is on the electric fans are always on aren't they?

So. I'm thinking there was a airlock somewhere but I'm hoping said airlocks not caused anything to get too hot.

Do you think it's still going to be the thermostat?
 
spud101 said:
Here's an update.

I was taking the pooches for a walk this morning and checked the coolant level (as I'm doing every day), she was parked on a slight incline but when I squeezed the top pipe to the rad there was lots of burbling coming from the cooling system (I've got to admit I was waiting for her to drop it all over the garage floor!! :eek: ) but it gurgled and bubbled for quite some time.

When it finished there was still plenty of coolant in the header tank but judging by the noises I thought a good few litres had gone somewhere. In any case, I've got some water in the back just in case she needs a top up and I went out with the dogs.

The temperature dial stayed mostly in the middle once warm but I got caught in some traffic by the A13 / A406 and it again started creeping up (nothing to severe) so I ramped up the heater and it blew red hot straight away, by then we were off and everything got back to normal. (I've got admit I was a little gutted as I thought I'd had a breakthrough.)


Anywho, I walked the pooches and when I got back to the car it was scorching so I put the air con on and drove back home, I got caught in some horrendous traffic but the dial didn't move a bit and it got me thinking. When the A/C is on the electric fans are always on aren't they?

So. I'm thinking there was a airlock somewhere but I'm hoping said airlocks not caused anything to get too hot.

Do you think it's still going to be the thermostat?
Click to expand...
My A/C fans are not on constantly.:)
 
I don't get you?

What I was getting at is I was asking, when the A/C is on are the electric fans on the radiator are always on? I thought they were.

My point being once I turned on my A/C the temperature gauge didn't move from the middle. (I have no idea why that's the case or even still what the underlying issue is, I'm just pleased that whilst my A/C is on my temperatures not flip flopping all over! :)

I appreciate you may not have your A/C on constantly but if it's a choice between that and getting my 'coolant temperature' warnings then I'll be leaving it on! :)
 
Last edited:
spud101 said:
I don't get you?

What I was getting at is I was asking, when the A/C is on are the electric fans on the radiator are always on? I thought they were.

My point being once I turned on my A/C the temperature gauge didn't move from the middle. (I have no idea why that's the case or even still what the underlying issue is, I'm just pleased that whilst my A/C is on my temperatures not flip flopping all over! :)

I appreciate you may not have your A/C on constantly but if it's a choice between that and getting my 'coolant temperature' warnings then I'll be leaving it on! :)
Click to expand...
Souinds like the viscous fan is shot. The aircon fans come on when the aircon demands due to gas pressure/temperature, on a hot day with a hot engine they are likely to be on thus compensating for the duff viscous fan.:)
 
spud101 said:
I don't get you?

What I was getting at is I was asking, when the A/C is on are the electric fans on the radiator are always on? I thought they were.

My point being once I turned on my A/C the temperature gauge didn't move from the middle. (I have no idea why that's the case or even still what the underlying issue is, I'm just pleased that whilst my A/C is on my temperatures not flip flopping all over! :)

I appreciate you may not have your A/C on constantly but if it's a choice between that and getting my 'coolant temperature' warnings then I'll be leaving it on! :)
Click to expand...

My A/C is switched on at all times and my fans do not operate constantly.:)
 
Condenser fans only come on when demanded when condenser temp rises....or in the P38 Petrols, later Diesels and L322 variants when coolant temp rises.

L322 Mode of operation....

Engine Cooling Fan Control
The engine's electric cooling fan is controlled by the ECM. When the compressor is engaged the ATC ECU sends a
fan speed message between 0 (off) and 15 (maximum speed) to the ECM, via the K bus, instrument pack and CAN
bus. The ATC ECU requests the cooling fan on when:

l The vehicle speed is less than 44 mph (70 km/h)
l There is no fault with the compressor clutch circuit
l Battery voltage is less than 16 V

The fan speed requested depends on the pressure in the refrigerant system. The higher the pressure the faster the
fan speed that is requested. When vehicle speed increases to more than 50 mph (80 km/h) the ATC ECU changes
the fan speed request to 0 until vehicle speed decreases to less than 44 mph (70 km/h) again.
If battery voltage increases to more than 16 V for 5 seconds the ATC ECU changes the fan speed to 0 until the voltage
decreases to less than 15.8 V.
Click to expand...
 
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Thanks very much for that Saint. That's the trouble with these forums, everyone's an expert but nobody seems to have any information to back it up. :)

After my 'airlock' situation I've not had anything at all on the coolant side, I'm going to keep my eye on the levels (which I always do in any case) and see how it goes.

Well. I will do as soon as I can get into her! I drove all the way to the South Coast of Kent and back yesterday without so much as a thing out of place and this morning she won't unlock, key won't work, nothing. I know these old girls need care and attention but she's demanding a lot at the minute! :)
 
spud101 said:
Thanks very much for that Saint. That's the trouble with these forums, everyone's an expert but nobody seems to have any information to back it up. :)

After my 'airlock' situation I've not had anything at all on the coolant side, I'm going to keep my eye on the levels (which I always do in any case) and see how it goes.

Well. I will do as soon as I can get into her! I drove all the way to the South Coast of Kent and back yesterday without so much as a thing out of place and this morning she won't unlock, key won't work, nothing. I know these old girls need care and attention but she's demanding a lot at the minute! :)
Click to expand...
There are indeed experts here with info to back it up. That's not a problem at LZ.
 
I've got to admit on the whole it seems like a great forum. I'm in IT and don't go anywhere near the forums for that anymore because there's a lot of experts who when someone posts the equivalent of 'My headlight's gone out', reply with something along the lines of: 'You'll need to replace the entire front end including the engine and it'll need respraying a different colour as well'! :)
 
Quick update. I've not had any problems whatsoever with the coolant temperature until yesterday. I was driving around town and I noticed it creeping up again. Low and behold the 'coolant temperature' warning came up and it again went down and up quite rapidly when I moved off etc.

I finished my drive and parked her up, waited a few hours for it to cool down and when I unscrewed the filler cap there was again a lot of gurgling but the level hadn't changed. I gave the pipes a good squeeze and there was a little more gurgling, screwed the cap back on and she's been bang in the center of the gauge all day.

I've done a little reading / searching on here and I suspect either the expansion tank cap is faulty or the tank itself. Either that or there's some small leak / hole somewhere but I don't see how as I don't know why it would just let air in and not leak water.

Anyone got any 'constructive' comments / help / experience please? :)
 
Thanks for that Saint. I watched the video but the strange thing with my old girl is that there's no water whatsoever coming out of the expansion tank and the pipes don't seem to get rock hard at any stage. I too have no sludge / mayonnaise and she's not using any coolant / oil.

I'll keep my eye on her and see what occurs.
 
I've just got her back from LRR (london range rovers) and they say they've fixed it so we'll see. On the whole I was really impressed with the garage.

Thanks for all the posts.
 
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