44 replies to this topic

[Carlos W]

It could be that the system needs flushed, timing or mixture out, or a failing water pump.

[Ipod]

is the heater matrix blowing hot (when open) and are both pipes to and from the matrix hot (inside by the passengers footwell)

I fitted a new rad to mine and had to put a hose into the heater inlet hose (under bonnet) to get the air/flush out.

Edited by Ipod, 28 August 2013 - 03:50 PM.

[paul_s]

The heater is blowing hot (and not warm), but I haven't actually felt the pipes. Will try that

 

I think the next steps are:

- Drain / flush the entire cooling system (tough as I'm in a flat with no access to a hose )

- Remove and test the thermostat 

- Refit thermostat and re-fill cooling system

- Throw a hissy fit and sulk when it doesn't work!

[jamesmpi]

Me thinking out loud.....
Could it be a duff water pump? And it's not circulating the water?

If the heater is blowing hot air then the coolant must be getting to it, but if the water pump is dodgy then it won't circulate it efficiently enough to keep it cool at high operating temps.

So I would avoid doing a system flush as this could be a waste of time and a lot of effort. Instead I would check your thermostat. Then do a compression test to rule out a possible head gasket failure.

If both of these are ok then somehow check the water pump. Not sure how you can do this other then remove it (not easy) or check that all the pipes get hot

Edited by jamesmpi, 28 August 2013 - 07:35 PM.

[Fossy313]

That seems weird mate because bulging up means its a pressure issue but if the cap is working then In not sure, I just had the same problem with splits but my new tank and cap is working fine now ! Hopefully someone may have a clue!

[paul_s]

Well, I can only assume the cap works fine as it's a new one. Of course it could be faulty but this seems unlikely.

Unlikely I'll have time to do anything before the weekend but I'll try the thermostat first, and compression test after if that proves inconclusive. If I can avoid taking everything apart I will!

[paul_s]

Tested the thermostat today, it opened up fine as expected.
I did a compression test and got the following:
210 200 200 220

I ran it with the top off and every few seconds there seems to be a few bubbles coming up into the expansion tank. Not if sure if this just a low coolant level (will top up and try it again).

Any thoughts? Is there a way I can test the water pump? I wiggled it with the belt off and it doesn't wobble back and forth. Slight squeak when turning it by hand but I don't know if that means anything.

EDIT: topped up and re ran the engine. No bubbles this time, until it boils over.

Edited by paul_s, 31 August 2013 - 05:44 PM.

[jamesmpi]

The compression test results look good so in theory the head gasket should be ok.

The water pump must be working as water is being circulated. Bits of a mystery. What does the temp gauge show when it boils up?

If it happens when the needle is showing "normal" on the gauge then I would suggest changing the tank cap again....

[paul_s]

I have a bit of an update; I've not been working on the car in a couple of weeks (have been cycling to work instead!)

 

I bit the bullet, and replaced the water pump, temperature sensor and the flylead for the temp sensor connector (as per the Rover bulletin).

Put it all back together, started up this morning.

 

After 10 mins of idling the fan kicked in, and the temperature gauge was 3/4 quarters of the way up (edging towards the red zone). Which means the temp sensor works at least! The old one never moved above halfway..

 

Is that normal for 10 mins of idling? It did seem to get very hot very quickly, but if the temp sensor wasn't working properly before then I don't know what it's supposed to read. It did look a bit smoky (whitish) this morning but that could've just been the cold damp air.

 

This is getting so frustrating! I didn't want to risk driving it to work, but my next step (maybe when I get home) is to take it for a 10 minute drive and see what happens. Other than that I'm out of ideas

[Yoda]

Is there a garage near you that could do a coolant test to see if there are any engine gases in the coolant. That amount of pressure could still be a small head gasket leak between a cylinder and the cooling system. As it seems that you have pretty much ruled out most other likely causes, this is where i suspect the problem may be. The leak may be just enough to cause the problem, but not enough to show up on a comp test.

 

A leak down test will also be useful to diagnose this issue.

[paul_s]

Hmm, there probably is, although I don't know there are any that local that are sympathetic to Minis. Will try the one I take the wife's car to maybe.

 

Sounds plausible from what you say, although not the problem I was hoping it to be! Thanks for the advice

[Yoda]

Any decent garage can do it for you, and they dont need to be mini sympathetic. the leak down test is old school, and the leak detection system (dye) has been around for years. No garage worth its sort should be without these.

Edited by Yoda, 13 September 2013 - 09:26 AM.

[jamesmpi]

If I'm honest that does sound a little quick to reach 3/4 of the way round the gauge. My fan normally kicks in when the needle just lifts off of the 1/2 way mark.....but then again if you ask another mpi owner his/her car might be different again

[Badboytunes]

If I'm honest that does sound a little quick to reach 3/4 of the way round the gauge. My fan normally kicks in when the needle just lifts off of the 1/2 way mark.....but then again if you ask another mpi owner his/her car might be different again

 

 

Our SPi fan kicks in just below halfway. The temp never gets above halfway,.

 

 

Cheers

[minimadles]

Check the small pipe to expansion tank coolant should flow through this when engine running and thermostat open they get blocked with flakes of rust used to be a problem with fords and k series rovers