[Keenan]

Good morning all,

I have a 1998 Gen 2 3.5. Currently my car stands for about a month without getting driven as I am away doing field work. The last time I drove my car everything seemed to be fine. My car then sat for about a month. When I drove my car again I felt some heat coming through the floor boards and my air con was not as effective as usual. I kept my eye on the temp gauge but it was in its usual position. When I stopped my car the engine, radiator and radiator cap all felt too hot for my liking. I felt the top radiator hose and felt there was less pressure than usual. I also checked the coolant reservoir and the levels were normal. I was not loosing any coolant but the pressure seemed to be lower than usual.

I found it odd that the temp gauge was normal but the car was definitely running warmer than usual. Could this be to a faulty radiator cap or the water pump. Am I right in saying that if the water pump failed, surely my car would have overheated fast. I did some reading and found that when you air con isn't working properly it could be a sign of a problematic water pump. If the water pump bearing is loose could the pump still work intermittently?

Are there any other options that could be causing this? The head cylinder gasket isn't an issue as their is no bubbling, loss of coolant or the coolant reservoir getting filled.

Thanks,

Keenan

[RoelfleRoux]

Keenan,

1)Did you check the coolant level in the radiator itself? When the motor is cold, open the radiator cap and make sure the radiator is full to the very top.

2)I'm prepared to make a wager that you cannot judge the coolant temp by feel . What were the conditions like during the drive: warm or cool, fast, easy drive or hard work or traffic?

3)The fact that you had heat dissipating through the floor and felt additional heat in the engine, but the cooling system appears OK, makes me think that the fan was doing extra work (engaged).

4)I will be surprised if a dodgy waterpump will cause the aircon to battle - unless the pump has a catastrophic failure and in the process destroys the v-belts. The aircon has it's own compressor and the aircon radiator sits in front of the engine radiator, so an overheated cooling system will also not affect the aircon.

I still think you must urgently check the level in the radiator.

[Keenan]

Thanks for your reply,

As the car was standing for some time, I checked both the oil level and radiator coolant level before I drove the car. I do this every time after the car has stood for some time before I drive it. Radiator coolant was filled to the top. I also checked the next morning and radiator coolant was still full.

I agree with you that judging engine temp by touch is not accurate at all especially seeing that my temp gauge was normal. The only thing that make me suspect anything was wrong was the heat coming into the car. The lack of pressure in the radiator hose got me slightly worried too. Could that be from the system working properly and realising pressure? I have told myself on a number of occasions that everything is ok as my engine temp was normal and maybe I just wasn't used to driving the car as I had been driving another car for some time. I just wanted to ask around as I didn't want to leave it and possible cause any further problems if there were any to start with.

To answer your question, it was freeway driving at about 100km/h from dbn to pmb. It was a warm day but it was the first time I had felt this heat in the car.

When I am back I will check my coolant levels again and give it a drive with a close eye on the temp gauge.

Thanks again.

[RoelfleRoux]

Keenan,

Then it seems that all is well. I really think your fan was working more than what you are used to. Durbs to Maritzburg in summer can be a challenge to any car's cooling system.

If it was running too hot or if the cap isn't functioning properly, then the coolant level would have lifted in the expansion bottle (directly after the drive).

[Keenan]

Thanks again, your replies have eased my mind. I guess I was worrying about nothing

[KaiV]

Do a hot compression test. You will find the head or head gasket is not too happy.

Had that with my Colt. Although a diesel, the symptoms were, Temp "normal" aircon not working and damn that heat.....
Ended up being a new head, gasket, radiator and turbo

[Keenan]

Thanks for the info. Just got my car back from my mechanic. An update on the issue:

1. Radiator rubbers were starting to bulge so radiator cap was replaced.
2. Radiator was removed and flushed.
3. Thermostat replaced.
4. Water pipes were replaced as old ones were starting to crack.
5. All belts were replaced (This was not causing the issue but they were replaced due to old age)
6. Lose cam belt was re-tensioned.

When I took my car to my mechanic, I told him the symptoms. After some discussion and checking of certain components he came up with a game plan of what to check. He said he would check my water pump too. When he checked the water pump he found that the cam belt was very loose
The cam belt was replaced about 30 000km ago (different mechanic that I have not used since). The belt was new but it was not fitted properly. The belt was so loose that when my mechanic turned the water pump the cam belt did not move. The cam belt was so loose that it wasn't driving the water pump. It only worked intermittently. This was the major factor that resulted in the engine running hotter than usual.

I am extremely relieved that I was able to sort out the cam belt before it came loose and cost me an engine.

Thanks again for your input

[NeilTruter]

I think you mean the 'fan' belt was loose, not 'cam', if it was the 'cam' belt you would have had major mechanical damage as the timing would have been out and pistons would probably have hit the valves.
Does your vehicle have separate fan belts driving the water pump and alternator ? Because if there is only one belt driving the water pump and alternator you would have noticed the charge light coming on if the belt was as loose as you describe.

[Nick Gibson]

The water/coolant pump in a V6 pajero is run by the Cam belt, the belt is reversed over the pump pully and runs on the back/smooth side of the belt, not the side with teeth for the Cam gear. It stands to reason that if the tension is low the belt could posibly slip on the water pump.

[4ePikanini]

don't take a chance. Get an aftermarket temp gauge and monitor it.