Air Con & Traffic Jam Over Heating & Brakes

[rjben]

Got stuck in traffic for an hour on Saturday in the warm weather. Before I realised what was happening the temperature gauge had shot up to 110, the most I’ve seen it at before is 105!!! Anyway, switched the aircon off and turned on the heaters, which brought the temperature down to normal. Does anybody else have temperature problems when stationary with aircon on? Is there a quick fix? Sods law, the one time you really need the aircon is when stuck in traffic.

I also noticed that the brake pedal travelled to the floor when the temperature reached 110. I take it that the fluid must have ‘boiled’. Would this be down to the excessive temperature or is it a sign the fluid has suffered water ingress and requires a change?

Cheers,

Rob

[tvrjohn]

RE brakes unlikely the engine heat, more like the servo
drained of vacuum as you were holding the car on the foot brake, and engine was just idling.

[rjben]

tvrjohn said:

RE brakes unlikely the engine heat, more like the servo drained of vacuum as you were holding the car on the foot brake, and engine was just idling.

Cheers John,

Nope, was not holding it on the breaks (use handbrake as it was standtill for 10 mins at a time)and they did not recover until engine temperature returned to normal, even after lots of pumping.

[JohnSW20]

Hi
Sorry new to the posting only had the Cerbera a month. Mine gets up 90 before I have left the end of my road but the fans seem to keep it between 105 and 90. What gets my pants bubbling is the fact that the oil pressure seems to drop the more the temp goes up. If anyone knows how to sort this out please help. I'm off to the New Forrest at the weekend for a bit of pony worrying and the wife would kill me if we had to keep stopping to let it cool down.

Cheers

John

[rjben]

JohnSW20 said:

Hi Sorry new to the posting only had the Cerbera a month. Mine gets up 90 before I have left the end of my road but the fans seem to keep it between 105 and 90. What gets my pants bubbling is the fact that the oil pressure seems to drop the more the temp goes up. If anyone knows how to sort this out please help. I'm off to the New Forrest at the weekend for a bit of pony worrying and the wife would kill me if we had to keep stopping to let it cool down. Cheers John

Same here John, fans keep everything in control unless its a hot day, the car is on stop for anything more than 10 mins AND the aircon is on.

As for the oil pressure, it will always drop when the car gets hotter due to the fact that the oil gets thinner. As long as it does not drop below 30 -35 ish, then your ok.

Cheers,

Rob

[trooper1212]

Brakes: Never had that problem after being in traffic. My clutch feel "different" if I get stuck in traffic for an hour or so, but after 5 minutes of driving it goes back to normal.

Oil pressure: The oil pressure will drop as the engine warms up, yet it should get to a pretty stable level after 10 minutes. Mine drops a little bit after pushing hard when warm though. How low does it get? Low oil pressure on idle isn't a huge worry, but you should have good pressure at 3000rpm, if not, something is wrong somewhere and I'd expect that you can see blue smoke from the rear under hard acceleration.

Air con: My Cerb has the annoying habit of stalling when using the air con at idle speeds, but connecting up the software this weekend showed that my lambdas are reporting faults, so that may well be the reason.


Temperature: The temperature gauge can be well out and not showing a true temperature, so I wouldn't worry about the actual reading, as long as the fans are coming on and the header tank isn't boiling.

>> Edited by trooper1212 on Monday 26th July 13:16

[rjben]

trooper1212 said:

Temperature: The temperature gauge can be well out and not showing a true temperature, so I wouldn't worry about the actual reading, as long as the fans are coming on and the header tank isn't boiling. >> Edited by trooper1212 on Monday 26th July 13:16

Yep, althought the fans normally come on at an indicated 100C and the temperature never goes any higher. This was still the case on Saturday but the temperature kept on rising and eventually got to 110C, which is when I lost the breaks. Makes me think that the long term excessive heat boiled the fluid?

[trooper1212]

rjben said:

Yep, althought the fans normally come on at an indicated 100C and the temperature never goes any higher. This was still the case on Saturday but the temperature kept on rising and eventually got to 110C, which is when I lost the breaks. Makes me think that the long term excessive heat boiled the fluid?

Do you have 2 fans? I've seen a cerb with only one fan and I'm not sure how it should work in that case.

On mine, the first fan comes on at around 92 degrees and the second at 95 degrees. It could be that the second fan isn't kicking in?

Incidentally a true 92 degrees shows as 0 on my gauge, and so does 95 degrees It's amazing how little you worry about the temperature when you don't have a working gauge to watch! I used to watch it like a hawk when it worked, after it failed I no longer worry and the Cerb hasn't overheated yet :touchwood:

[JohnSW20]

Thanks for the tip about the oil pressure I was sweating buckets when it dropped from 60 down to 40. It has not dropped below about 37 so with a few revs I can keep it up above the 40. I have only had the car about a month and I'm already £980.00 light after one service. £140 for spark plug leads!!

[Rob Dance]

". I'm off to the New Forrest at the weekend "

Keep off the end of the M3 where it joins the M27 , and also J2-J1 M27 West if you are travelling on Saturday morning, Guaranteed que !!

Likewise the return on Sunday nite

Its Holiday time !!

Depending where you`re coming from, the "long way round" is always a better option !

[Byff]

Without aircon, temp sits at 70 and rises to 95 before fans bring it back down.

With aircon, temp sits at 80 and rises very quickly to 95 before fans cut in.

Once driving in normal traffic again, temps go back to normal.

I've not had boiling brake fluid before, maybe a time to change the fluid? When sitting in traffic, it gets very hot under the bonnet.

[JohnSW20]

Rob Dance said:

". I'm off to the New Forrest at the weekend " Keep off the end of the M3 where it joins the M27 , and also J2-J1 M27 West if you are travelling on Saturday morning, Guaranteed que !! Likewise the return on Sunday nite Its Holiday time !! Depending where you`re coming from, the "long way round" is always a better option !

[JohnSW20]

Hi Rob
Thanks for the tip on the M3 I always use the A3 as I'm in the Wimbledon area. The ponys are going to be really worried with 2 cerberas going around on the same weekend. If your like me? I always tell the wife she looks tired and should have a couple of hours sleep. That should give you the afternoon to go and play.
It's my first time in the New Forrest any tips??

Cheers

John

[Tatlow]

rjben said:

Got stuck in traffic for an hour on Saturday in the warm weather. Before I realised what was happening the temperature gauge had shot up to 110, the most I’ve seen it at before is 105!!! Anyway, switched the aircon off and turned on the heaters, which brought the temperature down to normal. Does anybody else have temperature problems when stationary with aircon on? Is there a quick fix? Sods law, the one time you really need the aircon is when stuck in traffic. I also noticed that the brake pedal travelled to the floor when the temperature reached 110. I take it that the fluid must have ‘boiled’. Would this be down to the excessive temperature or is it a sign the fluid has suffered water ingress and requires a change? Cheers, Rob

Me and others on here have been in the same boat with our Cerbs recently - I posted a topic about it under "Steamer!", see later pages (sorry I don't know how to embed a link in this text). In a nutshell, the temperature started going up to 105 and the needle was flicking about like a good 'un. On a couple of occasions I got steam coming from the header tank and the coolant level fell quite a bit.

It was in at Topcats last week and there were two problems: Firstly, there was a small hole in the rad which let the coolant out, but only when it was really hot and the pressure increased; secondly, the metal fins in the rad were damaged by stone chips and the remaining gaps were mainly clogged with shite which stopped the fans from drawing the air through efficiently.

Now I've got a re-cored rad in there it doesn't go above 95 in heavy traffic. What a relief that is!

P.S.: A couple of years ago I had 105-level readings and it turned out that the second fan wasn't cutting in because a heat sender was shot. Very cheap to replace and it sorted out the problem.

P.P.S.: No experience of the brake pedal going soggy - although its often heat that causes these cars problems. Red hot gear sticks and handbrakes are an indication of that, I guess!

I'd check that the fans are both cutting in and that the rad is working efficiently, i.e. not mashed up to hell.

[rjben]

Cheers Tatlow,

I'm going to get the ecu lead so that I can check what temperature the ECU thinks the car is running at compared to the temp guage.

Thanks for the suggeestions, I'll check that both fans are cutting in and the radiators not damaged.

Does anybody know how I can check that BOTH fans are cutting in without removing the cover at the front of the engine bay?

Cheers,

Rob

[Tatlow]

rjben said:

Cheers Tatlow, I'm going to get the ecu lead so that I can check what temperature the ECU thinks the car is running at compared to the temp guage. Thanks for the suggeestions, I'll check that both fans are cutting in and the radiators not damaged. Does anybody know how I can check that BOTH fans are cutting in without removing the cover at the front of the engine bay? Cheers, Rob

Hi Rob,

In my car you can see both fans without removing anything if you open the bonnet, so all you need to do is leave it running and watch to see whether both fans come on. Yours might be different though.....

Hope it's nothing serious.

Jes.

[rjben]

Hi Jes,

Yep, mine is a bit different. The >2000 models have the fans and rad covered. I guess this must be easy enough to remove.

Cheers,

Rob

[trooper1212]

rjben said:

Hi Jes, Yep, mine is a bit different. The >2000 models have the fans and rad covered. I guess this must be easy enough to remove.

A wee tap with a crowbar and sledgehammer should do it

[rjben]

Thought I'd reply to this and give you an update.

Nowt wrong with the temperature. The guage reads 10 Degs to high! So check your guages people, no need to worry about problems that don't exist! The brake fluid had water ingress and since it's been changed I've had no more spongey pedal.

Relief!

Cheers,

Rob

[Julian64]

rjben said:

Cheers Tatlow, I'm going to get the ecu lead so that I can check what temperature the ECU thinks the car is running at compared to the temp guage. Thanks for the suggeestions, I'll check that both fans are cutting in and the radiators not damaged. Does anybody know how I can check that BOTH fans are cutting in without removing the cover at the front of the engine bay? Cheers, Rob

Yep lay down on the floor and gently reach underneath the radiator. If the air rushing past your fingers dosn't tell you keep moving your fingers forward until you can feel the pain of them touching the rotating fan.