Overheating?

[paulh260260]

Many thanks for that detailed reply im hoping that the age of the thermostat means it's simply failing and needs replacing.
As for the overheating I think will take it to horners for a check over the guys know their stuff when it comes to rovers

[T-Cut]

Hello Paul, sounds like you have a worrying situation.

Originally Posted by paulh260260

Just swapped out a failed three speed fan for a two speed with gold resistor it passed the demist test and road test kicking in at 100 degrees

So the low speed resistor is OK. For engine cooling, the low speed should trip on around 100C.

On a road test today around the M60, 40 miles at a steady 70 mph the temperature seemed way too high settling between 107 and 110 ,occassionally hitting as much as 113 on inclines.

So were you aware of the fan running at high speed at this time? It certainly should have been operating and would normally reduce the temperature to below 100C no matter how you were driving. The suggestion is a significant loss of coolant, but that didn't happen. So, your residual pressure test will be important in diagnosing the problem.

TC

[paulh260260]

Originally Posted by T-Cut

Hello Paul, sounds like you have a worrying situation.

So the low speed resistor is OK. For engine cooling, the low speed should trip on around 100C.

So were you aware of the fan running at high speed at this time? It certainly should have been operating and would normally reduce the temperature to below 100C no matter how you were driving. The suggestion is a significant loss of coolant, but that didn't happen. So, your residual pressure test will be important in diagnosing the problem.

TC

That's a good point TC, how can I tell if the high speed fan is working?... is there a specific change of sound at a certain temp if so what temp should the high speed kick in?

If the high speed is faulty how do i fix it, I thought the gold resistor avoided this problem, or is it case of opening the motor and swapping out brushes?

However I'm still not sure the fan can be faulty as even the low speed did not reduce the temp when activated.

First thing tomorrow Ill see if any air is let out when I open the header tank cap, when shes cold, and I'll sniff for exhaust smell, if there is such a smell does that suggest big problems?

If no smell ill bleed her again , just to be sure, but I cant believe that an airlock would result in such high temps... or could it?

Ill also test the top hose temp to see if it gets hot when it hits between 88 and 96 when the thermostat should be opening.

[paulh260260]

A bit of an update

I undid the header talk cap this morning as she had stood overnight and there was a very small release of pressure but no noticeable smell of exhaust gasses,could that suggest there is still a small airlock?

Haven't bled her again but did let her idle and even at 100 the top hose still felt cold/cool.

At 100 the low speed fan kicked in but had no effect on the temp as it continued to climb to 106 then I heard a noticeable difference in the fan which I am assuming was the high speed kicking in. Once again the temp continued to rise to 107 then 108 at which time I switched off.

No noticeable leaks either but I heard a gurgle when I listened at the header tank for a few seconds after switching off

So...could the gurgle suggest its still be a stubborn airlock, even at 107 degrees?

If its just the thermostat then that's an easy (ish) solution but more worrying is the build up of mayo, no point solving the overheating if the underlying cause is elsewhere.

Is there a way to determine whats causing the mayo by eliminating each culprit in turn ( IMG, Oil Cooler, Liners, then HGF)?

[vitesse]

Sounds like you still have air in the system - you report a gurgle. Some V6s are easy to bleed others almost impossible. My current V6 was the latter type, in my case when it finally eased it wasn't a gurgle more like a belch or strong burp. Before the burp I had no heat in the cabin.

I found that taking the car out for a spin around the village without stressing it, then when home while the engine was running I opened up the bleed screw in the hose, bubbles appeared then coolant. Repeated this perhaps three times before all the air was expelled from the bleed screw area. Not in the handbook, or recommended by some, but it worked for me.

Good luck

[SD1too]

Originally Posted by paulh260260

... even at 100 the top hose still felt cold/cool.

Hi Paul,

Can I just confirm that you're referring to the large hose which runs alongside the left-hand bank and enters the radiator at the top on the driver's side, and it's cold?

Can I ask you to repeat the test at 100˚C but this time grasp the hose containing the bleed screw (this is the bottom hose). Is this one cold/cool?

Originally Posted by paulh260260

At 100 the low speed fan kicked in but had no effect on the temp as it continued to climb to 106 then I heard a noticeable difference in the fan which I am assuming was the high speed kicking in.

Paul; did you fit a 2 speed fan complete with control box? Where did you get it from? The fast speed shouldn't operate until 112˚C

Originally Posted by paulh260260

... but more worrying is the build up of mayo ...

Is the expansion tank full of mayonnaise? What about the dipstick, any on that?

Simon

[paulh260260]

Originally Posted by SD1too

Hi Paul,

Can I just confirm that you're referring to the large hose which runs alongside the left-hand bank and enters the radiator at the top on the driver's side, and it's cold?

Yes that's the hose im referring to

Can I ask you to repeat the test at 100˚C but this time grasp the hose containing the bleed screw (this is the bottom hose). Is this one cold/cool?

Yep did that at the time, that one was warm

Paul; did you fit a 2 speed fan complete with control box? Where did you get it from? The fast speed shouldn't operate until 112˚C

The 2 speed fan was from Arctic who helped me fit it to an 03 connie at a nano met, I've simply taken it off that car and fitted it to this 02 connie so should be compatible

Is the expansion tank full of mayonnaise? What about the dipstick, any on that?

No mayo in header tank but plenty under oil filler cap. The oil on the dipstick is dark brown when wiped on a paper towel and has a very strong smell of exhaust gas...this doesn't look good to me!!

Simon

No mayo in header tank but plenty under oil filler cap. The oil on the dipstick is dark brown when wiped on a paper towel and has a very strong smell of exhaust gas...this doesn't look good to me!!

[SD1too]

Thanks for your reply Paul. I must admit to being puzzled by the answers you've given.

Regarding the hose temperatures, are you sure that you haven't accidentally got them the wrong way around? I don't see how coolant going in to the radiator at the top can be colder than that exiting it at the bottom!
If the bottom hose (with the bleed screw in it) was the cold one then that would explain your severe overheating.

That's good news that the 2 speed fan came from Arctic. When you noted a change of speed at 106˚, were you using the built-in instrument pack diagnostics? Was heating/air con. in 'ECON' mode?

Let's concentrate upon solving the overheating problem Paul and leave the mayo until later.

Simon

[paulh260260]

Originally Posted by SD1too

Thanks for your reply Paul. I must admit to being puzzled by the answers you've given.

Regarding the hose temperatures, are you sure that you haven't accidentally got them the wrong way around? I don't see how coolant going in to the radiator at the top can be colder than that exiting it at the bottom!
If the bottom hose (with the bleed screw in it) was the cold one then that would explain your severe overheating.

That's good news that the 2 speed fan came from Arctic. When you noted a change of speed at 106˚, were you using the built-in instrument pack diagnostics? Was heating/air con. in 'ECON' mode?

Let's concentrate upon solving the overheating problem Paul and leave the mayo until later.

Simon

Cheers Simon.

Right I've had another prod around and as you say I may have been giving slightly confusing or wrong info so here's the latest...

The top hose does indeed get warm, however it very squishy, i think i maybe felt an airpocket the last time hence the cooler feel. I thought as a pressurised system all hoses should be firm.

The bottom hose is warm from the thermostat out to the bleed screw then it feels cool as it goes down to the rad.

Oh and the air con and heating are all off whilst I'm checking, although I did quickly switch the heating on on the first test to check if hot air was blowing both sides and it was.

Finally I was using the IPK to check the temp

Hopefully that's made it clearer

Paul

[SD1too]

Hi Paul,

Yes, that's helped my understanding but I still cannot work out what's going on with your cooling system.

Originally Posted by paulh260260

The top hose does indeed get warm, however it very squishy ... I thought as a pressurised system all hoses should be firm.

First of all the top hose should be almost too hot to touch, not just "warm". Also don't expect this hose to be firm. The pressurisation is mild, only 15 psi above atmospheric pressure at the most.

Originally Posted by paulh260260

The bottom hose is warm from the thermostat out to the bleed screw then it feels cool as it goes down to the rad.

This is bizarre! I have to ask, is this a car with problems that you've just bought or has this overheating recently occurred on an otherwise reliable engine? Has K-seal been administered?

Simon