The temperature gauge on my 2004 b is never steady in normal running. It climbs up to about half way, then drops, then climbs again, then drops..... It's always been like this, so I'm not overly worried, but I've never seen this sort of behaviour on any other vehicle I've owned.

Does this happen to anyone else? Any ideas what the cause might be? I'm wondering whether the cooling fan might be cutting in too early, but that's only because I can't picture the 'stat opening and closing all the time. (In standing traffic, the fan cuts in when the gauge is just above half way.)

H

My B, for the first few miles, and especially in this cold weather, goes to about an eighth and then goes up to a quarter once its run for a bit. It only goes up to halfway if I put the cold heater on full blast. Never goes above halfway at all. To be honest though, with the problems I've been having with it lately, plus my almost-knackered radiator, I wouldn't use my B as the "normal" measure of how it should run.

The other day I tested when my fan came on, it was also when the heater dial was about halfway. I haven't noticed it going up and down as frequently as you describe but I'll have a check on my way home in the morning.

A couple of things spring to mind. One: the thermostat has failed. Two: a bad connection on the temperature sender unit.

Mine fluctuates, in the summer month it sat at about 1/4 on the go, if I were in traffic it would sit between 1/4 and 1/2 (and fluctuate when the fan kicks in)

This time of year just seems to sit at 1/4 regardless..............

The other possibility is that you have air in the cooling system. Try bleeding it - the bleed valve is on top of the radiator. Be careful if the system is hot as hot coolant may come out of the bleed valve.

HTH
Doogal

OK - just spent about 5 hours today polishing (with Zymoil) and waxing (with Maguires) and left her idling for about half an hour when I had finished the bodywork and turned my attention to the interior.

After about 25 mins at standstill the temp was at 1/2 way and the fan kicked in, temperature stayed at the same place - didn't get any higher.

Mrs LRB sent me to Tesco for 'stuff' 5 mins down the road and the temp was just below 1/4 again (mind you it was about -2 but I still had the hood down!!)....

......B's run at 1/4 when moving. In traffic or on idle for long periods of time they creep up to 1/2 and the fan cuts in as LRB explained, but once on the move again the temp goes down to the norm of around 1/4

LittleRedB said:

mind you it was about -2 but I still had the hood down!!)....

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:nutter:

Robot said:

:nutter:

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Livin' the dream man!!!

R30GUE said:

......B's run at 1/4 when moving. In traffic or on idle for long periods of time they creep up to 1/2 and the fan cuts in as LRB explained, but once on the move again the temp goes down to the norm of around 1/4

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ah... so, thats normal then... a was wondering about that myself.
Since it only ever goes 1/2 when idling for a long time, and almost immediately dropping when moving (irrelevant of outside temps).. i was wondering Not worried though, i've had worse temp indicators on cars.. i "fondly" remember a Rover 820i...

The only thing i was wondring about if the temp probe just fed the indicator, or wether it was also fed into the ECU. Cuz in that case i can imagine the ECU getting the message that the engine is "cold" and thus keeping the "choke" open ... resulting in gas-guzzling.

If that would be the case... a quick solder of an extra resistor over the probe to give a more realistic temp would be the answer to that.

Morning everyone!

This morning on my way into work my temperature gauge went higher than normal.

Usually it sits at 1/4 then goes up to 1/2 in stop start traffic as described in this thread. This morning in the pouring rain and crawling up to a junction it went right up to 3/4, then once I got moving again it dropped back down to 1/4. Should I be worried? Does it need to be checked over?

Thanks

xS

p.s. what crappy weather! I'm sure its been raining constantly since I bought the car beginning December!

Morning Shel,

One of the experts will be along to give you some better advice but last time I saw that kind of behaviour was about 6 months ago on my Rover. It was due to a head gasket problem which on a car that old meant game over. Still at least it made me go out and buy the Barchetta.

I'd check your coolant reservoir, make sure that's still as full as it should be, and that the coolant is not all brown and rusty-coloured. If it is that'll be oil mixing with the coolant I think, and that's a head gasket problem.

If it's empty, you could just have a leak in your coolant system maybe, resulting in the overheating.

That's all the advice I can give I'm afraid with my somewhat limited experience. All I know is when it happened to me it was indicative of a big problem and I hope it's not the case with your B. Good luck!

Hey xS,

sound advice from Jiggy - it could be a number of things but if its not consistent then it is either a fluky one off maybe caused by the huge amount of water probably covering every inch of the engine in this awful weather.

First thought is it's is most likely to be a sticking thermostat if it has only done it the once, the only way to check this is to take the thermostat out, drop it in a jug of boiling water and see if it opens.

Could be the temperature sender switch but not likely, although if you have noticed it running a bit rich or feeling sluggish this would be an indication.

Check the coolant level in the header tank and look inside the cap for 'buttermilk', also check inside the oil filler cap for the same. This is a sure sign of a head-gasket but to be honest its not a weakness that the b tends to suffer from so I would not worry too much just yet.

The other alternatives are a water pump that is on its way out (but you would usually see a loss of coolant from the water pump area as the seal tends to go at the same time as the pump), or a blockage in the rad or cooling system.

To be honest if its only happened the once and you did not actually overheat I would not worry too much, check your oil and water and keep your eye on it, if it starts happening more consistently then it will need to be looked at but my gut feel is it would be a temp sender switch or thermostat.

HTH

Thanks for the advice.

It's only happened once that I've noticed. My engine was a replacement reconditioned one about 4k ago so I wouldn't have expected anything to be going wrong yet?

Do you think I'm safe to drive home and check it there later? Otherwise I have to go out to the work carpark in the rain surrounded by loads of dodgy engineering types fagging in the doorways!

xS

Yeah I'd say it's not that urgent that you have to check it this minute. If it's the head gasket it'll be a gradual thing anyway that will get worse over the next few hundred miles so I'm sure you can just keep an eye on it as LRB says and see what happens.

Shelxs said:

Thanks for the advice.

It's only happened once that I've noticed. My engine was a replacement reconditioned one about 4k ago so I wouldn't have expected anything to be going wrong yet?

Do you think I'm safe to drive home and check it there later? Otherwise I have to go out to the work carpark in the rain surrounded by loads of dodgy engineering types fagging in the doorways!

xS

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I would think that you will be OK as long as the temp does not shoot up within 5-10 mins of you starting....

Thank you!

I saw that you are doing some contracting LRB - are you a techie?

xS

Another thought, listen for the fan when the engine gets hot. Take of the oil cap and look for white gunk around it.

Other than that, are you a member of the AA yet

i wouldn't worry... tempgauge behaviour in the B is a bit irksome, only worry when i NEVER moves up or shoots up within minutes.

If you want to be sure, keep an eye on it the next few days...
and before you leave home/work, check the oilcap for "mayo"

then again, if you only drive short distances, then you might also find mayo in the oilcap - that is condensation... a 50 to 100 mile motorway run and a more regular oilchange takes care of that

Shelxs said:

Thank you!

I saw that you are doing some contracting LRB - are you a techie?

xS

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Not for a while, currently contracting as an IT Project Manager.........long story but not a job a love!!