Weird temperture behaviour 2.5 v6

[SD1too]

Originally Posted by Pruts3r

Update

This is very useful information Merijn, thank you.

Your running temperature is too high and the fan is unable to reduce it.

• System not pressurising due to a leak, e.g. inlet manifold gasket, but could be anywhere.
• Thermostat not opening fully. Check the bottom radiator hose; the one with the bleed screw fitted into it. Is it almost as hot as the top hose or luke warm?
• K-seal or equivalent has been added to the cooling system, causing it to malfunction. Is this a possibility?

Simon

[Pruts3r]

Okee. Manifoldsgaskets wil be swapped for new original green MG rover ones this week.

You know what i find weird... Coolant hasnt dropped for a while now. Tree trips ago it was between MIN and MAX and after a drive it was ABOVE max. Since then took 3 trips. A long one hour and a half (and 1 1/2 hour back). Two half an hour trips (both also half an hour for the returnjourney)

Coolant has been sitting at the same above high level now for about two weeks... Somewhere in the system coolant is being swapped for air i gues?

[Yorkshire GOC]

As you see my car is a 1.8t - but your water loss symptoms are similar to mine a couple of years ago - the IM gasket was failing and losing coolant- swopped out for the newer type Roew gasket which i recall was black?

[Pruts3r]

Well just drove to the place were we do al the tinkering on our cars (about 40 minute drive) and when we arrived we sat for about 30 minutes. Then when we unscrewed the coolant cap there was a lot of pressure. Cap was gently unscrewed but coolant poured out of the smal drain tube all the same... (got a black coolant reservoir).

Overpressure on cooling system isnt usual with failing inletmanifoldgaskets right???

[T-Cut]

Originally Posted by Pruts3r

Overpressure on cooling system isnt usual with failing inlet manifold gaskets right???

No, not from the inlet manifold. Cold system overpresure is due to exhaust gas. As I suggested in post 40, you ought to look specifically at the residual pressure in the cooling system. Do a test with that objective.

With everything stone cold, adjust the coolant level to Max.
Drive for 10miles or so at normal speeds, fast and slow.
Park car and leave untouched for 6-12 hours or overnight.
When stone cold, open the coolant filler cap and observe any significamnt release of pressure. There should be none.

If there is a repeat of what you last desribed (post 54), have a carbon dioxide (exhaust gas) test done. Or buy a test kit and do it yourself.

TC

[SD1too]

Merijn, also don't forget to check the last two points I made in post no. 51:

• Check the temperature of the bottom radiator hose (you could have done that yesterday). It should feel almost as hot as the top hose.
• Be honest: could K-seal or Steel Seal or equivalent have been added to your cooling system at any time? These can produce symptoms which will mislead you into believing that you have head gasket failure.

Removing the expansion tank cap on a hot engine (30 minutes cooling time is not enough) is a pointless exercise as T-Cut has suggested. The overflow which you experienced will occur with a perfectly functioning cooling system unless the cap is literally unscrewed inch by inch, very, very slowly. Even then, you will hear the coolant boiling as the pressure is equalised and the process often has to be halted as a result.

Simon

[Pruts3r]

Simon,

I only had the car since octobre so at some point someone could have used something like k seal. I didnt offcourse because i read everywhere that that stuff effictively kills Kv6 engines.

Felt bottomhose after like 20-30 minutes. It was lukewarm. Less hot than top hose. The other big pips running behind the bottom of tne radiator were hot like top radiator hose.

Tcut,

Didnt know what you precisely ment in post 40. Now that i do know i ll do that test with the 10 mile drive.

Will Keep you updated! Oh, no point in still swapping inletmanifold gaskets i prosume?

Thnx to both of you for the help!

Happy easter,
Merijn

[SD1too]

Originally Posted by Pruts3r

Felt bottomhose after like 20-30 minutes. It was lukewarm. Less hot than top hose. The other big pips running behind the bottom of tne radiator were hot like top radiator hose.

Thank you Merijn, that's very helpful. The bottom hose (fitted with the bleed screw) should not be lukewarm.
It's difficult to be certain but I'd suspect that you might have either a blocked oil cooler or a thermostat which is either stuck shut or isn't opening fully.

Do you fancy some DIY over the Easter weekend?

Simon

[Pruts3r]

Hahaha well no time for that unfortunatly...

So forget about inletmanifoldgaskets??

Al the symptones put together:
-losing coolant for months with every now and then coolant levels rising (and staying there for days before dropping again)
- sometimes a bit of presure left in cooled down system (some hissing like slowly opening a cold cocacola bottle)
- perfect temperature after fixing low speed fan but now after swapping heater matrix high temperatures when driving in towns. Ls fan unable to cool down. Only like 40mph or faster driving brings temp down to 95 again
- mayo build on and under oil cap up that keeps coming back slowly

This points to thermostat and oil cooler? I want to be a bit sure before doing al kinds of pointless repairs. How to test oilcooler?

[SD1too]

Originally Posted by Pruts3r

I want to be a bit sure before doing al kinds of pointless repairs.

That's a very sensible philosophy Merijn which I try to follow too.

This points to thermostat and oil cooler?

Let's put it this way. Your bottom radiator hose (containing the bleed screw) should not be luke warm. That indicates that there is no, or inadequate coolant flow through it. Before this hose lies the oil cooler and after it, the thermostat. If either of those components is impeding flow, I'd expect the warm hose which you have reported.

There comes a time when some practical investigative work needs to be done, and you have reached that point. That's not the same as "pointless repairs" which I define as replacing components on the assumption that they must be faulty but with no proof. So that brings us neatly to your next question:

How to test oil cooler?

I have not done this job myself, but I have seen the components on my own car and others.
Remove the hoses and pipework connected to the oil cooler. Examine carefully for blockages. Check the drained coolant for signs of the 'mayo' detected under the oil filler cap. Consider flushing the pipes, hoses and the oil cooler with clean low pressure water. If in any doubt the cooler can be by-passed temporarily to enable the engine temperature to be checked for improvements. You'll need to find something suitable from a plumbers' merchant for this.

How does that sound? It will only cost you a few Euros.

Simon