[Mk2] [NA] Overheating - diagnosis options? Mk2 N/A

[Carpie]

Hi,

Any help with this would be really appreciated, as I love the MR2 as a car (this is my second) and am really hoping I haven't bought one with problems!

I have a Mk2 3S-GE, bought it 3 weeks ago and it has run fine up until the weekend just gone, when I took it on the first long drive I've done in it. The temp gauge has always sat 2-3 bars below the centre which I believe is right for these, however after about 3 hours of driving, mainly motorway cruising, the engine light came on and I noticed the temperature gauge had risen to the top. Pulled over and shut her off, there was steam rising from the bonnet etc. It was stormy so we left her there overnight as I was only about a mile from my destination.

The next day we topped up the coolant up (with water) and started her up, was running fine but there was a thick white foam coming from the expansion cap. My initial thoughts were that this was an oil/water mix due to a head gasket failure. Took her for gentle drive and was running fine.

I realised that on that journey was the first time in my ownership of the car that I had touched the in car temperature dial to warm the car up, previous to that it had been pushed all the way to the coldest setting. This led me to suspect it had been losing coolant via a leak in the heater matrix on that drive down, which would make sense as it seemed to be running fine with it set to cold.

I decided to brave the journey home, and it ran fine for 4 hours, again motorway driving, with the temp needle sitting in the usual location. Then just as I left the motorway the temperature began to rise at a fair rate, so I pulled over. There was a lot of pressure in the coolant system, steam was rushing out of the overflow pipe and it took a while before I could open the expansion cap and refill the coolant. It took roughly 4 to 5 litres of water.

Then drove it the 15 minutes home with no trouble and this morning drove it 30 minutes to work without an issue.

Sorry for the long post.... I would like to ask the collective wisdom on here what my best options are for diagnosing it?

No evidence of water in the oil (dipstick comes out with normal looking oil).

I presume a pressure test would let me rule out head gasket failure, and a pressure test on the coolant system would let me diagnose if there is a leak in it? I found a garage who said they would pressure test it for £30, is this a fair price?

Thanks!
Matt

[ormzy]

What I would do. And I'm no expert so this is just friendly advise.
1. Bleed the cooling system.....With the car cold and the coolant cap removed,remove the frunk panel to reveal the heater bleed plug, attach a clear plastic pipe,elevate and secure to bonnet. Remove radiator top plastic cover and on right hand side should be bleed point. Again attach clear pipe if the radiator has the port fitted if not then you need to undo the bleed screw until coolant flows. undo the white screw on heater bleed point and fill the cooling system until coolant is full and coolant is present in the bleed pipe or pipes you have raised. replace filler cap one part turn so not fully closed then start and run the car on fast idle for about 30 seconds then switch off and allow coolant to settle. remove filler cap and top up if level has dropped. replace cap partly and again start and run 30 sec, stop, top up u get the idea.
Do this a few times untill your happy u have all the coolant u can manage in then lock off the bleed points on heater and radiator. Close fill cap propery this time and start and run engine untill the radiator gets hot and temp gauge reads normal cooling fans cut in etc. Note you must get this bit right as just filling these cars up with coolant is no good, all air must be bled out the system otherwise it will give you the symptoms youve described. The links to the procedure for bleeding are readily available on here or other forums, I did this from memory so please check.
2. Check for leaks!! that means everywhere, all hoses engine side, under the car behind the dirt shields, the hoses from hell above fuel tank ect.
3. Make sure radiator cooling fans cut in, and engine bay fan. pull plug on the little black thing on the under side of engine lid and fan should come on.
4. check for excessive white smoke/steam from exhaust this would indicate coolant entering cylinders due to head gasket failure.
5. Check thermostat is opening. If the radiator and radiator pipes dont get hot then the thermostat is stuck closed and requires replaceing.


If your symptoms continue, time for a garage to take a look.

hope this helps.

[DB Mr2]

This will help with replacing the coolant. Your in luck as the majority of users on this forum have probably had to do this at some point in mr2 ownership!

http://www.mr2.com/forums/attachments/m ... cement.pdf

Be sure to refill with the correct type of coolant, the Toyota forlife (red) is usually recommended.