KV6 overheating and losing coolant

[Randyjim]

Originally Posted by ricebridge

However, I did notice that one copperish-looking pipe (bear with me pls for not knowing all the exact technical terms here) that goes across the engine below it at the front, and which is connected to the hose leading down from the expansion tank, was greenish. Is that even an original part? Why put a piece of copper pipe into a hose-based cooling system? Won’t that cause corrosion from aluminium parts?

It seems like at some point the rigid steel pipes to the oil cooler have been replaced with a homemade copper set. These are prone to corrosion, and the stainless steel sets are quite expensive, so using copper can save money.

With regard to the overheating, is the radiator getting hot? You have very high temperatures at 133C. This could be reached quite quickly in the engine block and cylinder head if there's a circulation problem. This could be due to an air lock, a failed closed thermostat or a failed water pump or another blockage of some sort.

[SD1too]

Thanks for testing the fan Jonathan. Jim makes a very good point:

Originally Posted by Randyjim

... is the radiator getting hot? You have very high temperatures at 133C.

Warm up the engine until the radiator fan starts running. Open the bonnet and locate the bottom radiator hose. It's the large diameter hose with the bleed screw in it, alongside the battery box. Is it uncomfortably hot to touch? What's its temperature compared with the radiator top hose?

Originally Posted by ricebridge

BTW, an independent mechanic suggested it might be the water pump, since there is no visible motion in the water in the expansion tank. Any thoughts on that?

The coolant circuit doesn't flow through the expansion tank so that observation is irrelevant. Also, water pumps usually give trouble by leakage. It's rare for the impeller to become detached from its spindle so that possibility is not a good bet.

Can you report back on the hose temperature please Jonathan? Oh, and don't let it get to 133 degrees will you.

Simon

[ricebridge]

Quick hose check without a thermometer shows them both to be equally hot. Not scalding, though; more like a nice cup of tea. Was that good or bad?

[ricebridge]

Originally Posted by Randyjim

It seems like at some point the rigid steel pipes to the oil cooler have been replaced with a homemade copper set.

Yes, I'm beginning to think so too. What are they supposed to look like? Is there anything else that's supposed to go there that some previous owner or mechanic has ripped out?

Starting to feel sorry for this poor girl...

[SD1too]

Originally Posted by ricebridge

Quick hose check .... shows them both to be equally hot ... Was that good or bad?

Good in that there is flow through the radiator so your thermostat must be opening, but bad in that we're no further forward!

Time to find out where that trail of water is coming from (which you mentioned in an earlier post). You've checked in the 'V' haven't you?

Simon

[ricebridge]

Originally Posted by SD1too

You've checked in the 'V' haven't you?

Simon

I have, yes, but as far as I can see, there’s nothing there. However, I am starting to direct some suspicions towards the filler cap. Could such a trivial fault cause all these problems?

(BTW, I’m not entirely sure that the trail of alleged coolant was from my car, or coolant at all.)

I’m getting a filler cap as soon as any suitable webshop will allow. But apart frim that, I suppose such stuff as Radweld or their equivalents are anathema? Or is it worth a go?

[CLINTE]

I would not put Radweld , K seal etc into the car as that will potentially give you others problems .

[SD1too]

Jonathan; did you buy this car from a dealer or privately?
Have you received any service history, particularly on the cooling system?

Originally Posted by ricebridge

... I suppose such stuff as Radweld or their equivalents are anathema?

Yes they are and, as Clinte says, are likely to increase your problems rather than eliminate them. The solution is to find the cause of the overheating and fix it properly. The non-standard copper pipes surrounding the oil cooler are not an encouraging sign.

The story so far:

• No evidence of coolant loss.
• Radiator fan runs upon 'demist' test.
• No leaks in the 'V'.

Your thermostat might not be opening fully, or indeed be stuck partially open, but these are just guesses. Does the temperature gauge reach 'normal' in the usual rapid period of time? Does the heater work normally?

Simon

[ricebridge]

Originally Posted by CLINTE

I would not put Radweld , K seal etc into the car as that will potentially give you others problems .

Thanks for confirming my suspicions.

[ricebridge]

Originally Posted by SD1too

The non-standard copper pipes surrounding the oil cooler are not an encouraging sign.

Indeed. I think this girl has suffered some abuse (which only makes me even more keen to restore her to glory btw.) What exactly is that piping supposed to look like?

Originally Posted by SD1too

The story so far:

• No evidence of coolant loss.
• Radiator fan runs upon 'demist' test.
• No leaks in the 'V'.

Your thermostat might not be opening fully, or indeed be stuck partially open, but these are just guesses. Does the temperature gauge reach 'normal' in the usual rapid period of time? Does the heater work normally?

Simon

We can add one item to the list: Overheating only takes place when the engine is under a load. Works fine during normal cruising.

The temperature rises to working levels normallly. However, interior heating is nothing to write home about. It is very, very patchy, and most of the time only blowing cold air. Every now and then it produces some heat, but mainly around my feet; it doesn’t reach the higher nozzles.