Overheating problem - help if you can?

Overheating problem - help if you can?

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Scooby P1

Original Poster:

2,617 posts

236 months

Saturday 26th July 2014
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Hi all

Bedford was very hot today and I wasn't the only Noble with an overheating issue.

I recently had the pro alloy header tank fitted by a local garage but today it kept boiling over. By the end of the day after 3-4 laps the temperature gauge would suddenly shoot up to 120 and by the time I nursed it back to the pits the header tank level had gone below the sight glass. This happened at least three times.

I tried to bleed the system by hand squeezing the fat pipe entering the radiator on the drivers side with the header tank cap off. This seemed to get the return pipe in the tank circulating the water, i.e. the air lock had been got rid of but this didn't solve the problem.

Was it simply because it was a hot day or something more sinister?

After driving back to London, temp gauge stayed constant but the tank was fairly empty again.

Any ideas how to solve this problem would be welcome?

Could it be related to an electrical issue? There's certainly a bad earth somewhere as the battery doesn't last longer than two weeks without being on charge and all the dials stopped working briefly this evening but turning off and starting again solved that.

All rather annoying as was lapping very fast but the car kept overheating.

Thanks.

Metalman

1,173 posts

225 months

Saturday 26th July 2014
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The only thing I can add is that my PA header tank will fluctuate from below the sight glass to centre of the sight glass and above the sight glass. It's been on the car at least 18 months so shouldn't have any air locks, and on trackdays it does seem to chuck some out the overflow pipe (just a dribble) but I've rarely topped it up.

Scooby P1

Original Poster:

2,617 posts

236 months

Saturday 26th July 2014
quotequote all
I had to attach a pipe to the overflow to stop it spraying all over the place it was spitting so much out repeatedly!

Regretting fitting it now as never had any heating issues before this......annoyed I left the original header tank at the garage to be thrown away.. Only got the PA one so I could have it on black and it look better!

Davie M12

194 posts

140 months

Sunday 27th July 2014
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My PA header tank was the same, fitting a higher pressure cap fixed it.

andygtt

8,345 posts

271 months

Sunday 27th July 2014
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The ecu tells the gauge what to read, so it sits at 90 deg until it's actually overheated then goes off the gauge, what's actually happening is you engine has gradually got hotter and normally you are unaware, it's just this time it went over the threshold in the ecu which I'm guessing is at 105-110 deg.

Get the high pressure cap, that def helps, and also the lower temp stat.
It's won't have been caused by your header tank IMO.

Plumber1

630 posts

168 months

Sunday 27th July 2014
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Is the high pressure cap the one with the lever from Merlin Motorsport ? So really the pro alloy tank is not as good as the original ?????

Scooby P1

Original Poster:

2,617 posts

236 months

Sunday 27th July 2014
quotequote all
Anyone got a link on where to get the high pressure cap from?

What a stupid design. Upgraded equipment is worse. Not a fan of that mentality.

Once the cap is upgraded, will that stop the temp suddenly jumping to 120?

Bear in mind this has never, ever happened before this bloody PA tank was fitted!

2.5bluenob

1,620 posts

183 months

Adrian W

14,414 posts

235 months

Sunday 27th July 2014
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Scooby P1 said:
I had to attach a pipe to the overflow to stop it spraying all over the place it was spitting so much out repeatedly!

Regretting fitting it now as never had any heating issues before this......annoyed I left the original header tank at the garage to be thrown away.. Only got the PA one so I could have it on black and it look better!
If you feel that way about it why don't you fit a standard one on and see if the problem re occurs

GTO600

1,877 posts

258 months

Sunday 27th July 2014
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Andy's right about the cap but no it won't stop your car overheating.
I suspect your car is standard therefore with no air cooled oil cooler & normal mess grilles etc so if you take it on track on a hot day like yesterday it will get too hot & regardless of what header tank you have it will have overheated.
If you want to track your car (especially on a hot day) you really need an oil cooler & larger / no mesh to all the air inlets & outlets.
Kevin

Hollowpockets

5,908 posts

223 months

Sunday 27th July 2014
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Again, the problem isn't the tank, it's the heat in a standard car on track, fit the high pressure cap and a cooler if you can.

In addition, you will have a hose somewhere that is dripping because it's not tight enough, which causes the fluid level to slowly drop even on normal driving, not a big enough leak to cause a puddle though, so go round checking all jubilee clips too.

TuxMan

9,011 posts

245 months

Sunday 27th July 2014
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Scooby what radiator have you fitted ??

Scooby P1

Original Poster:

2,617 posts

236 months

Sunday 27th July 2014
quotequote all
Standard radiator mate.

But I've never had an overheating problem ever before yesterday.

And I have been on fairly hot track days before. And been stuck in huge traffic jams in 30+ degrees and its never waivered a degree over 85.

The standard expansion tank has no overflow outlet and that's where water pours out of my new PA one. Had to fit a hose to point down so it doesn't spray all over the engine bay!

Scooby P1

Original Poster:

2,617 posts

236 months

Sunday 27th July 2014
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2.5bluenob said:
What psi spec do I get?

andygtt

8,345 posts

271 months

Sunday 27th July 2014
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To be clear, the reason the gauge never wavers above 85 is because it reads 85-90 regardless of temp until it's goes over a threshold... In fact the thermostat of a stock engine doesn't even start to open until 93 deg.... So at 85-90 no water would be going round the rad at all!
Also fans are set to come on at 95-96deg further showing the gauge reading is rubbish!

If you want to properly monitor your car water temps fit some sensors in the hoses under the jubilee clips and read it real time.

TuxMan

9,011 posts

245 months

Sunday 27th July 2014
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Perhaps at 11 years old the rad is just plain knackered !!!

Jim O.

485 posts

204 months

Sunday 27th July 2014
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If you haven't already, I'd start with the basics - check the water pump, test the thermostat ( or just replace it, since you have to remove it to test it), and pressure test your cooling system, including the filler cap. If you're worried about air in the system, the best way to go is to drain the system and refill using a vacuum filler.

After you're sure that all the basics are ok, you might want to consider upgrades, like a higher pressure cap or an upgraded radiator.

Adrian W

14,414 posts

235 months

Monday 28th July 2014
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what is the standard pressure cap rating?

2.5bluenob

1,620 posts

183 months

Monday 28th July 2014
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Scooby P1 said:
What psi spec do I get?
The highest pressure one.

Jarcy

1,559 posts

282 months

Monday 28th July 2014
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Mine was the other Noble with overheating problems on Saturday.
I have standard expansion tank, but a newish Pro-Alloy rad. I also have the oil temperature/pressure guage.

Before Saturday I had never experienced water temp problems. But the same as Lawrence describes, after 4-5 laps the temp would suddenly jump from 90 to 120. I also have oil running up to 120 but keep a close eye on that - In the past it's oil temperature that's told be to back off (water remaining fine).

My expansion bottle behaved fine with no evidence of boiling, but did get a dribble out of the overflow pipe. The level remained constant.

I'd suggest that your PA expansion tank only requires the high pressure cap as others have suggested. It was a very warm day, and so I too think it's just the ECU saying 'enough' for a standard car. My plan is to fit a larger oil cooler (do 3Rs have one at all, or are they just on the M400 as standard?). Hopefully by keeping the oil cool, the block temp won't challenge the water system so much.

It was really frustrating not being able to fully enjoy Bedford - a great circuit, my first time there. Only managing 3 - 5 laps at a time, and by the later sessions, short-shifting and watching the guages and not the corners/breaking points.
The M400 didn't have the same problems as us, but he's already got a large oil cooler, plus various other mods.