[MikeRo]

Hi guys

I have 2007 Gen4 3.2 GLX. Engine temperature while driving around town in traffic or on the open road is normal with no issues, even in long periods of standstill on the highways in traffic. I also use the car to tow a Fleetline caravan .... and here is the occasional issue. While towing, on the open roads it generally runs normally but sometimes on hills, with extended torque the temperature gauge start to rise quite rapidly. Fortunately once over the hill and back to 'level' terrain, the temperature then returns back down to normal again ... Some trips can go by uneventfully, but others, this problem pops up.

Any ideas on what could be causing this? I must add, that this only started after my last service and they told me the air flow meter/regulator (something like that ) was faulty and it was replaced at a cost of R8500.00.

Could there be a link?

Mike

[Nick Gibson]

Check the basics first, new thermostat, new radiator cap and see what she does as the items are cheap and is a good thing to do periodically anyway. Also maybe your radiator slightly blocked up with mud or seeds? Does your viscous fan kick in when the engine is under load, you should hear when it it running.

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[MikeRo]

Check the basics first, new thermostat, new radiator cap and see what she does as the items are cheap and is a good thing to do periodically anyway. Also maybe your radiator slightly blocked up with mud or seeds? Does your viscous fan kick in when the engine is under load, you should hear when it it running.

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Hi Nick

Thanks i will check some of the cheaper options first. I really am not technical at all so to answer your question about the 'viscous fan' ... i would really have no idea what i was listening for Is there some way of checking this?

Mike

[Roelf_le_Roux]

Hi Mike,

When you tow the caravan, do you leave the gearbox in D or do you drive in "manual" mode and drop to 4th on slight inclines?

In D you will find that the torque converter clutch disengages on slight inclines and this adds heat to the transmission and subsequently to the radiator.

[MikeRo]

Hi Mike,

When you tow the caravan, do you leave the gearbox in D or do you drive in "manual" mode and drop to 4th on slight inclines?

In D you will find that the torque converter clutch disengages on slight inclines and this adds heat to the transmission and subsequently to the radiator.

Hi Roelf

I actually only ever use D. I have never used the manual option while towing. I must add i have had the the van a while and never had a heating issue even while using D only, but i will definitely give it a try and see if it helps. Should i use the manual option all the time when towing, or just slip it into manual when approaching hills?

Mike

[CATS]

Mike

What is the mileage on your Pajero? Was the cooling fluid ever replaced? If so was it flushed and replaced with the original spec Mitsu coolant? I believe this is very important on these vehicles.

Why was the airflow meter replaced? Did you notice anything strange in the behaviour of the vehicle and asked mechanic to check for that or was this replacement initiated by the mechanic?

CATS
PS Overheating is a swear word in my vocabulary and I have nightmares about it!

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[MikeRo]

Mike

What is the mileage on your Pajero? Was the cooling fluid ever replaced? If so was it flushed and replaced with the original spec Mitsu coolant? I believe this is very important on these vehicles.

Why was the airflow meter replaced? Did you notice anything strange in the behaviour of the vehicle and asked mechanic to check for that or was this replacement initiated by the mechanic?

CATS
PS Overheating is a swear word in my vocabulary and I have nightmares about it!

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Hi Cats

Thanks, let me try answering your post :

1) The mileage on the Pajero at the moment is 266000Km
2) As for the cooling fluid, i am really not sure. The car has been to both Mitsubishi in Boksburg, and a private mechanic in Boksburg (who has a Paj himself) only for servicing.
3) I noticed a marked reduction in performance especially while towing with the car. I am not sure if you are familiar with the N1 through Pretoria by Atterbury heading south, but there is quite a climb. The car with the caravan really battled, and i couldn't get much more than 80km/h up there coming back from a weekend away at BalaBela. Even at that time though, the heating was normal not even a slight increase in the gauge. When i took the car for its service, i asked them to take a look at the performance issue, and thats when they told me their diagnostic machine reported the airflow meter was faulty. I must say, since its replacement, she now flies, and that same hill i can make at 120km/h + (if needed) but now the heating increases.

Mike

[Roelf_le_Roux]

Mike, I prefer to go manual when I tow. The car has trained me very well. I know when the TC clutch is going to release and change down before that. Sure, mine is petrol and enjoys higher revs, but I do it purely to prevent that clutch from going in and out all the time under heavy load.

[CATS]

Mike. I know that uphill well. Anybody who ever towed past Pretoria will know it.

Mmm. I have no absolute solution to your overheating problem! Does it use any water on a consistent basis?

As mentioned before maybe start by flushing the radiator and refilling with Mitsu coolant and replace the radiator cap with a new one with correct presure and see what it does.

The viscous fan should be heard at a steady roar over the engine noise almost like a chopper starting up, so listen out for that. Even though it could be the cause I believe that once past 80kmh the wind pushing in from the front should be sufficient. Only at low speed should it play a roll.

Hopefully this sorts you out.

Otherwise next step is probably new radiator and or waterpump. But lets tackle the cheaper stuff first.

CATS



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[Roelf_le_Roux]

My story about the gearbox is relevant because it will add heat to the system, but I think in your case it shows up a shortcoming in the cooling ability of your car. I assume the new airflow meter allows for enough diesel to be injected under load (as apposed to the old one) and now the cooling is falling short.

I fully support Cats' advice as a solid starting point and would like to add fan belt tension, cowling around the fan and the seals around the radiator to the body.