[Transkeicowboy]

(I have just edited this topic as it is no longer a relevant name for this thread. This was how this all began...read along to see how the issues changed and what happened along the way. Went from overflowing bottle to failing radiator to improper coolant mix - hopefully this will help some others who have similar symptoms in future)

I have got to say that i am not happy with the mitsu suppliers this afternoon.....fitted the second new viscous clutch for the fan and hey presto....soon as i get to a decent hill the temp shoots up again....stop the engine and the fan spools pretty freely....hence it is not working....AGAIN!!!!!

[RoelfleRoux]

Transkei,

I'm really not a fan expert, but my gut feeling is that something else is brewing here. It is very unlikely that two new fans will be broken. Should the fan lock up completely or does it simply become more "resistant"?

I doubt if a fan offers more "suck" than natural flow at higher speeds. Could it be that your cooling capacity has been reduced and that the extra load on steep hills result in temperature increase?

If you are happy that the outside of the radiator is clean and free of blockages, then you should start investigating the coolant flow of your system. First step is thermostat - if that doesn't help you could consider a decent radiator flush and as a final step the water pump.

I'm sitting on the outside and am most probably far off the mark, but I think the dealer is guilty of miss diagnoses rather than faulty parts.

I hope you get this thing sorted.

Best,
Roelf

[Transkeicowboy]

Hi Roelf

Thanks for the comments. I have replaced the radiator cap, had the radiator acid bathed and have also replaced the thermostat (all with genuine mitsu parts).

When the first fan clutch didn't work I removed it and replaced it with the old one I still had. My mechanic had bolted the old one togetehr so that it works constantly. I then had no overheating issues for two and a half weeks and in fact did exactly the same test drive route I did yesterday and at similar ambient temperatures. Yesterday half way up a steep hill the temp gauge began to climb over the half way mark and staedily head towards the top. When I did the test with the bolted together clutch I in fact drove up and down that hill twice at high engine speed and the temp gauge didn't budge.

That is why I think it can only be that again I have a clutch that is not operating correctly. In addition to that when I test the fan after I have stopped driving there is no more resistance to turning than when I turned the fan before I started the vehicle this morning.

Anyway I am now off to the dealers to discuss

[4ePikanini]

what coolant/antifreeze mix are you running?

[macjohnw]

Sounds like a heated argument might follow - just don't fan the flames too much

Hope it gets sorted soon.

[Transkeicowboy]

@ Mac he he thanks for the smile...

@Marius I am using the Mitsu coolant product from the dealers...

went to them this morning to discuss this issue and they wanted to book my vehicle in for a checkup.....NEXT WEEK WEDNESDAY....obviously that didn't happen!

was booked in immediately and I am now waiting to hear their findings

[RoelfleRoux]

Transkei,

Please allow me to elaborate on my line of thinking re. your problem.

Symptoms:
1) The temp gauge indicates over heating up a steep hill.
2) The clutch on the fan isn’t engaged when the temp reading goes up.
3) A locked clutch fixes the symptom.

Now for my elaboration:
The coolant("water" for the rest of this post ) flow for most cars is from the bottom of the radiator through the pump and then into the engine. In the engine it is forced via passages until it emerges out the front again. It then passes through an open thermostat and back into the top of the radiator. This is also where most cars have the temp sensor. The clutch on the fan will lock-up if the body of the fan (where the fluid is housed) heats up sufficiently to expand.

From this we can deduct that the coolest point of the water is when it enters the pump and the hottest point where it passes through the temp sensor on the way to the top of the radiator.

If we assume that the clutch of the fan is operating correctly, but the temp is too high when it passes the sensor, then we have to conclude that the water is too hot when it emerges from the engine, but not when it enters the pump. For this to be correct, we need to have a reduced flow rate. In other words the water spends too much time in the engine and then again too much time in the radiator.

Your situation isn’t totally out of control yet. I say this because a fixed clutch, with “over” cooling ability, manages to allow cool enough water to enter the engine so that it doesn’t overheat before emerging again.

I thus maintain my opinion that I think you have reduced flow capacity and the two most likely candidates are thermostat and pump.

I’m not an engineer and really know very little about cars. So this is just my take on your problem from 1000miles away.

I really hope the Mitsu boys get to the bottom of this.
Roelf

[Transkeicowboy]

Thanks Roelf. Just spoke to them and they think the air may not be flowing properly through the radiator as they think it looks "blocked" on the front. However I have just had the radiator checked and acid bathed and Silverton have said there is nothing wrong with it.

Secondly they have noted that my water pump was replaced with a non-mitsu pump at my 190 000km service. They reckon (as do you) that that could be the problem.

I am going to get the mechanic to change that and lets hope that sorts this out!

Thanks very much for your comments. Much appreciated.

[RoelfleRoux]

If my story above is remotely true, then the problem isn't a blocked radiator. The water won't cool down sufficiently in the radiator and will cause the fan clutch to engage.

I assume they have a pump in stock (I hope).

[Transkeicowboy]

thier reasoning is that a viscous fan operating correctly is never as strong as a bolted/locked fan. The mechanic reckons about 30% of the front of my radiator is damaged and is not allowing air to flow through it properly and therefore not cooling properly.

So the dealers have told me I need a new radiator. They first said they only recommend using a genuine Mitsu one. After a bit of discussion they said that one from Connocks in East London would also be fine.

Connocks version is 50% of the cost of the new original Mitsu part.