Overheating on a track day.

[phazed]

I use my MK1 purely for Track Days. It has been 100% reliable and have done about 25 in the last two years.
 

On Friday the car started overheating slightly in the afternoon. I was pushing hard as usual and the temperature gauge slowly crept up a couple of segments, so I pulled off. Water wasn’t visible in the header tank and after letting it cool down, it took a couple of pints to top up. I’m not sure that the fans are working properly as when I came in, they were not turning. I went out another three times but kept short, shifting to keep the temps down which prolonged my sessions out and as soon as the temperature gauge started rising, I came back in to the pits.  Sometimes it didn’t need a top up or other times just half a pint.

 

Question, what is my problem? Some say that the fans generally don’t need to come on at speed as there is enough air flow to keep everything cool.

 

Are these engines prone  to head gasket problems? The car has only done about 85K miles and generally the engine is as sound as a bell.

 

Any hints as to where to start looking for the problem?

 

I decided also on the day that I should fit an oil cooler and will order one tomorrow to assist  in cooling.

 

By the way, new radiator was fitted three years ago when I first prepared the car for the track. 
 

I look forward to any suggestions. Cheers.

[StevesTruck]

Keep it simple - if it's not leaking it, it's burning it. 

 

Check for signs of cross contamination, do a sniffer test (the kits are cheap enough). Did anyone mention it was smoking?

 

It is possible that a joint's getting a bit poor and it's only leaking when it's being pushed hard, so it's work having a good look around all the pipework for any leaks. 

 

Does it get hot and/or spin it's fans when it's sat idling in the sun, or if sun's in short supply, idling with the bonnet down and it's nose up against a hedge? If you've still got a/c, does the fan spin when you stick it on full cold?

[phazed]

Thanks for responding.

No air-conditioning, I stripped that out. I will run it up this morning and see if the fans come on. As mentioned, the last few sessions I drove changing gear at 4.5 K revs and I could stay out for 15 minutes or so without noticeable loss as long as I came in as soon as the needle started going off normal.

 

It is in the garage at the moment running.

 

I have checked all the houses and there isn’t any noticeable leaks.

 

I did stay out on the last session until the needle moved a few millimetres of normal and I had to top it up with about half a pint of water this morning.

 

Regarding the fans, what sensor do they work from. Can I bridge this and check if they are both working?

 

Do the fans work with one coming on first, and then the second if needed?

[Crasher]

Don’t trust the dash gauge, it displays rubbish. If it moves above 90 the truth is 117 and rising.

[Breezy_Pete]

1 hour ago, phazed said:

Regarding the fans, what sensor do they work from. Can I bridge this and check if they are both working?

Radiator thermoswitch.

Not sure on your wiring, but if you have thickish wires, red to red/white should bring both fans on at low speed. Red to red/yellow should be full speed, but probably needs ignition to be on.

[phazed]

Thanks. Will check.

[Paws4Thot]

@phazed With how cheap they are (~£12 the last time I checked), maybe buy it a new expansion/pressure bottle?

[phazed]

Coincidentally, I fitted a new expansion bottle when I first bought the car about three years ago, that still seems sound and intact. It did occur to me that the pressure cap might well be faulty and not doing its job under extreme pressure!

 

Also thinking that a proper oil cooler would help matters as an upgrade. They do come as standard with the small oil/water cooler but a proper 19 row or similar oil cooler must be much better. Any recommendations for a kit would be good. 

[phazed]

Went for a spirited drive down the country lanes with lots of higher revs, (not a patch on track work though) and temperature gauge stayed at normal.

 

Checked expansion bottle on return and water level was spot-on.

 

I have heard of water pumps where the impellers breakdown and seem to work normally until pushed hard and obviously they aren’t shifting as much water as they should.

 

I did replace the pump with cam belt three years ago and not a lot of miles ago so I am thinking that the likelihood of this is very low.

 

Any thoughts on this? 

[kentphil1]

I would be inclined to check the plastic housing that the temp sender is mounted in, when that starts to leak, it can give that type of odd temp issue, until the crack gets larger (in the housing) and becomes a full on leak. you should see some staining by the head if it's starting to fail.

[ctn3107]

Given that you've already identified a potential issue with the fans and the need for an oil cooler, it's a good idea to address those areas first. If the problem persists after checking and potentially repairing these components, you may want to consult with a mechanic or cooling system specialist for a more in-depth diagnosis. Best regards!

[phazed]

I am picking up in oil cooler kit later today and my mechanic son is calling round a bit later to give me his tuppence worth. We will see.

[phazed]

As StevesTruck stated, keep it simple.

 

My Eagle eyed son spotted some staining around the plastic housing on the right hand side of the cylinder head. This is the plastic housing where three hoses terminate with also a sensor located there. I have removed it and it seems that at high revs and prolonged use was letting go at the O ring. 
i’ve ordered a new better quality part as this was a pattern part fitted about 18 months ago.

 

Note to myself, always use genuine or top quality parts on track cars!

 

 

Thank you for your input guys. I will still fit the oil cooler as this will definitely benefit my set up.

[Breezy_Pete]

Worth checking the fans too, even though you've probably found the coolant loss problem.

If original there's a strong chance the low speed functions are 'history'.

[Silver Bullet]

Or perhaps one of these kits?

[kentphil1]

On 21/08/2023 at 14:50, phazed said:

As StevesTruck stated, keep it simple.

 

My Eagle eyed son spotted some staining around the plastic housing on the right hand side of the cylinder head. This is the plastic housing where three hoses terminate with also a sensor located there. I have removed it and it seems that at high revs and prolonged use was letting go at the O ring. 
i’ve ordered a new better quality part as this was a pattern part fitted about 18 months ago.

 

Note to myself, always use genuine or top quality parts on track cars!

 

 

Thank you for your input guys. I will still fit the oil cooler as this will definitely benefit my set up.

Yep, that's the one i was talking about, unfortunately, they are almost a consumable item after 6-7 years, as the o ring fails and the housing distorts because of the extra heat.

[phazed]

21 hours ago, Silver Bullet said:

Or perhaps one of these kits?

that part in the middle at the top is the part that failed. That looks a great idea, where is that available from.

 

Just going to pick up the oil cooler kit delayed due to 1st world problems! Lost house Internet for four days due to the National Trust cutting the overhead cable across woodland and also lost phone Internet access for a few days coincidentally at the same time due to a technical glitch with my provider! I don’t know how we survive in the western world …

[Silver Bullet]

 I got it from Creation Motorsport here is the link, and its on special offer   :-

 

https://creationsmotorsport.com/catalogsearch/result/?cat=&q=AL0158

 

Yup its scary seeing young kids with mobile phones etc, we used to make our own toys ie trollies, build rafts (that sunk), I guess thats progress NOT!!

 

Good Luck