Final solutions to overheating problem...

[Spanish Dorikin]

My stage 1 car started to overheat about 1 month ago when when air temp raised 40º (summer in Madrid is a hell).

We change termostat, viscous fan and utterly clean the radiator. The car has improved, but anytime I put full throttle in fifth (150 mph) the temp gauge inmediately goes up to the red. Just after releasing the gas, it returns to normal position.

We have test that it is not a head gasket failure. The mech says its just a basic thermodynamic problem, i.e the car has reached its cooling eficency due to extreme outside temp.

Big problem is Im selling the car (with already two buyers to test the car in few days) and that story does not sound too convincing.

After doing a bit of search here, fitting the Koyo racing rad seems to be the next logical step (just 270 $ on ebay). What would you do?

How about cheking the air fuel mixture on dynamometer? Maybe the car is going a bit lean and therefore it heats cilinders, but I have Walbro fitted!!

Do I need to run the car with lamdba unplugged in summer?

[SMiFFAD]

I have a very similar problem, good as gold untill you start doing silly speeds for any time....

You seem to have tried everything, rad, thermostat etc, rad would be the next logical step (its what im going to do if its not the thermostat).

You let people test drive your car at 150mph ?!

[Spanish Dorikin]

You let people test drive your car at 150mph ?!

Unless the name correspond to Fernando and the surname to Alonso, no.

(Apart from jokes, when I bought the car 2 years ago, the former seller drove me and a friend 150 mph for a while and did a drifting 180º turn to show capabilities of the S14 )

[LowRollaBoy]

You can upgrade to an R33 fan and shroud.

Im in australia, we get mid 30 deg summers and ive never had any overheating probs with my s14.

Also another option is to invest in two electronic fans, rather than the viscous fan.
Or perhaps your thermostat needs changing. It might be jammed and not open all the way.

[Spanish Dorikin]

Termostat is already changed. We have also removed the apexi filter and back to stock box. The car has improved, now only heats up when thrashing it.
It seems the temp prob is located on the combustion chamber. Running lean at the top end?
We need to test AFM to see if its broken (maybe because of running the Apexi) and therefore causes the car to run lean.

Next monday we are gonna check air fuel mixture at the rollers.

Temp sensor has also a reputation for not being too reliable. Its already bought and waiting to be fitted.

This is a nightmare problem that has appeared just when selling the car!!!
Although the mechanic is a friend, all this tests and parts cost a lot of money and time

The first time that I suffered the heating anomalie was about 3 months ago making a 10 minutes high speed test with tubby blowing 1.1 bar (1.2 initial peak). With an air temp of 12º I dont think it was so crazy.

[Mr OCD]

Its pretty obvious what is happening here... you are running high speed for long periods of time with higher boost than standard so the EGT's are going through the roof.... these cars arent designed to run at 150mph for long periods of time!

[Spanish Dorikin]

The car reached the rev limiter in fifth surprisingly easy

[Mr OCD]

The car reached the rev limiter in fifth surprisingly easy

It will - but that doesnt mean you sit at the limiter for 10 minutes at WOT!

[greg_p]

An oil cooler can be another idea. A great part of the engine cooling capacity goes through the oil...
Oil is cooled by the sump and the oil-water exchanger (near oil filter).
This oil-water heat exchanger is double or triple sized on a pulsar gtir, but it is not adaptable on a S14 sr20det...
A big hole on the hood can be another solution, the air flow created and the fact is cool the engine bay can help. Try this with a cooling panel also .

[Creasey]

We change termostat, viscous fan and utterly clean the radiator.

What do you mean by 'clean'? Have you actually had the rad flow tested?

[Jez]

Have you got the undertray and fan shroud on? They make a huge difference.

[Spanish Dorikin]

What do you mean by 'clean'? Have you actually had the rad flow tested?

Its a good question, I will confirm with a ring to the mech.


Have you got the undertray and fan shroud on? They make a huge difference.

Sorry, my english is poor, can anyone describe undertray and fan shroud?




BTW Jez, yesterday I talked with Oscar Bartol (he was on my mate garage) from Vagspeed. They contacted you some time ago to map a couple of Power FC (one from a Scooby AFAIK) here in Madrid. Amazing how little is world...
Would be a pleasure to meet you in person if you finally go around here

[voodoo_melon]

Have you got the undertray and fan shroud on? They make a huge difference.

[hijack]I've not got an undertray, would it be advisable to get one? Got electric fans though.[/hijack]

[Jez]

Have you got the undertray and fan shroud on? They make a huge difference.

Sorry, my english is poor, can anyone describe undertray and fan shroud?

The undertray is the big thing made of cardboard that covers the under side of the engine.

The shroud is the big platic thing that clips on the radiator and goes around the standard fan.

BTW Jez, yesterday I talked with Oscar Bartol (he was on my mate garage) from Vagspeed. They contacted you some time ago to map a couple of Power FC (one from a Scooby AFAIK) here in Madrid. Amazing how little is world...
Would be a pleasure to meet you in person if you finally go around here

Yeah, itd be good to meet Where in Spain are you?

[Jez]

[hijack]I've not got an undertray, would it be advisable to get one? Got electric fans though.[/hijack]

If you're not getting over heating probs, don't worry about it

[dan_t]

i would have thought not having an undertray would help? more air movement?

[Spanish Dorikin]

Yeah, itd be good to meet Where in Spain are you?

...here in Madrid.




The undertray and fan shroud have always been fitted.

I will post rollers result on Monday. I hope the car goes lean, at least that would mean we will have discovered the cause of the problem.

[Spanish Dorikin]

Back from rollers...

Tha car only outputs 220 bhp and 31 kgm @ 0.8 bars and with exhaust bung fitted!!

The air fuel mixture is a bit on the rich side, perfect for summer and to prevent disasters.

The car doesnt have pressure on the coolant circuit even after making the manifold glow. The lack of pressure makes the liquid boil very easy, and hence the temp problem.
At first sight you could say is a head gasket failure, but the car does not lose any coolant nor suffer from other clear-classic head failure indicators.

Even the enginner at the rollers was amazed by the wierdness of the cause responsible for lack of pressure in the refrigeration circuit.

[Mr OCD]

Perhaps the propeller blades have come off the pump? - hence lack of water pressure?

[SMiFFAD]

You rloosing NO coolent... not even a bit over time...

Ive found (since removing the cowling) that my rads got a very small crack in it somewhere inside the core, and it spits small amounts of coolent out when its at high pressure, not enough to make it drip, just leaves small ammounts of dryed coolent in the engine bay (further helpd by the mist hitting the fan... coolent sprinker system )

Just a thought...