SP Overheating

Hammer · Postby **Hammer** » Fri Mar 16, 2007 12:09 pm

Hi guys

When driving my SP on the freeway travelling between 110-120km/h with the aircon on mid to high 30 degrees temperature, the car's temp gauge seems to creep up quite quickly to the H zone.

The only way I can stop it from totally boiling over is to turn off the AC. Then the needle once again swings back slowly to the normal middle position.

When stationary, the temp gauge remains in its usual position, and as usual when I took it to get looked at, they can't fault it - apparently they sat in the one spot for 30mins with the air on and the needle didn't budge.

So it seems it only happens when it's dríven constantly at those conditions revving between 3000-4000prm.

Any one else have experienced this, and/or any tips on how I can fix it?

Boags · Postby **Boags** » Fri Mar 16, 2007 12:27 pm

It doesn't have anything to do with your other problem does it? The car is running a bit leaner (hotter) because of the air/fuel sensor? And it's only causing problems at 3-4000 cause thats where the car is tipping into boost...?

Just a thought,

Boags :?:

Hammer · Postby **Hammer** » Fri Mar 16, 2007 12:36 pm

Well they say, they've fixed the Air/Fuel sensor problems when they had the car for nearly 2 months.

But who knows. :roll:

Postby **Boyracer** » Fri Mar 16, 2007 12:57 pm

Need to check the fans come on when the A/C is switched on...

Mid to high 30s with A/C on is really pushing the cooling system to it's limits.

Benny · Postby **Benny** » Fri Mar 16, 2007 3:28 pm

The SP's cooling system is marginal at best.
If you have some gunk in your radiator, it may overheat, so get it flushed out and re-filled.
That's the first thing to check.

I have had overheating issues on the track, and I'm getting a larger radiator and an oil cooler fitted shortly, but I've never had any overheating issues on the street, even in bumper to bumper traffic on a 40 degree day with the A/C going full blast.

Garry · Postby **Garry** » Fri Mar 16, 2007 7:38 pm

Have you checked for any coolant leaks? If they didn't replace your turbo cooling pipes when they replaced your turbo I'd start looking there. The stock ones are shite and prone to going brittle and cracking. I've had 2 sets on my car already.

sabretooth · Postby **sabretooth** » Fri Mar 16, 2007 9:31 pm

Is the intake mouth of your car standard?

Seeing as it happens at speed - sounds like heat in > heat out. Get the radiator checked for blockages, and then ensure the water pump is all happy.

Hammer · Postby **Hammer** » Sat Mar 17, 2007 12:27 am

It happened again tonight.

With the usual F3 pace at 5pm on weeknights, the flow of traffic was anywhere between 40kph to 100kph. Averaging 60kph, with bumper to bumper formation for the first hour and a bit of getting out of Sydney.

The needle did creep up to nearing the furthest allowable margin in the temp gauge, but it didn't go pass and I didn't have to turn of the A/C.

Mazda did replace my A/C condenser (located between the intercooler and radiator) with a brand new unit. Apparently the old one was leaking. But apart from that, it seems all the pipes are original.

Garry, which intercooler pipes in particular are you referring to?

Garry · Postby **Garry** » Sat Mar 17, 2007 8:13 am

Garry · Postby **Garry** » Sat Mar 17, 2007 8:16 am

Garry · Postby **Garry** » Sat Mar 17, 2007 8:17 am

I'm talking about the rubber pipes for the coolant for the turbo. But having read your post on the other thread about getting a new engine, you should ignore my suggestion.

Like BR said, are both cooling fans working when the A/C is on and it's overheating? Assuming you dont have anything blocking the air intake to your radiator it sounds like something didn't get put back together properly in the rebuild to me. Take it back to Mazda and leave it there until they fix what they broke.

sabretooth · Postby **sabretooth** » Sat Mar 17, 2007 9:24 am

Fans can only push a fraction of the volume of air that goes through a car's radiator at speed.

MX5-SP · Postby **MX5-SP** » Sun Mar 18, 2007 4:04 pm

sabretooth wrote:Fans can only push a fraction of the volume of air that goes through a car's radiator at speed.

actually, it's pull, and I understand the fans are designed to simulate a constant airflow that is sufficient to mitigate overheating in stalled traffic conditions...assuming one doesn't sit at traffic lights revving the engine at 4,000RPM....well, not all the time!

AJ · Postby AJ » Sun Mar 18, 2007 4:06 pm

mr darby is quite right, altho if the car starts to heat up in stalled traffic, 1800 - 2200 WILL help by getting the water circulating

MX5-SP · Postby **MX5-SP** » Sun Mar 18, 2007 4:14 pm

I haven't actually experienced any overheating per se (...on account that I don't drive fast anyway), however...SHOCK-HORROR...last week when I travelled interstate to wash my car (QLD>NSW...my Mum's place)... A routine check under the bonnet...I noticed my coolant reservoir was \"mighty dry\".... :shock:

I must have just caught it in time as the temp gauge had not varied off its normal range, but I'm intrigued why the \"sudden loss\"of coolant. No obvious signs of leakage...believe me - I looked! But I must admit to a degree of nervousness as I haven't had this problem before. I will continue to monitor.