Overheating Radiator

[Noddy]

Hi Guys! can anybody help me please, I've got a CF Bedford Motorhome Running a V6 VP Commodore Motor, since I've had this Beast I've had nothing but overheating problems, even with the old Red motor which was the first motor in it I had over heating problems, I've had the radiator out twice for a clean and changed water the water pump and thermostat but still over heats, funny enough it only over heats on a hot day, come winter it sits on half way, but the minute the outside temperature rises so does the engine temp' the Radiator looks in good condition, I have no idea how old the radiator is? So the Question is Do I install a new Radiator or what do I do? Any Ideas would be very helpful.
Thanks

Noddy

[rumax]

Have a look in the old posts- there are many discussions re overheating. There are some good suggestions before you outlay on a new radiator as well.

[BusyKiwi]

What radiator and fan are you using?
My VN V6 van runs always to cold if anything, am running standard VN radiator with it's electric fan.

[mezzmo]

Same here, VN radiator with thermo and no issues, you dont have an air blockage do you? that happened to us in the beginning.

[rumax]

another thought- are you using a matched sender and gauge....... could give the impression it's hot, when it is at the correct temp.

[willo]

Hi mate,
V6 Commodores run at 97 degrees.  Check the number on your thermostat.  So, this means that there isn't much room for temperature rise before looking like it runs hot.  In a standard commodore the gauge is calibrated to show this temp as normal range but if you run an aftermarket gauge it shows the actual temp so looks hotter.

I still run the original Beddy 3 core radiator in mine and it's OK.
Look at your airflow around the front of the van.
also, how heavy is your vehicle?
Are you running a trans cooler?
Even at light usage if your vehicle is heavy the motor us working hard to move it and cut through the air.
All cooling systems are working at capacity in a full size Beddy motorhome.

Overheating 101.
Overheating can only be caused by 3 things.
1) not enough water flow - blocked radiator etc
2) not enough air flow - too small a radiator, fins blocked by grass seeds etc
3) mechanical issues -water pump, head/head gasket, incorrect thermostat/radiator for the motor/usage.
1 and 2 are sometimes related to each other.

As has been previously said, check out the archives as Beddie motorhomes and overheating are fairly commonly discussed

Cheers

Neil

[BeerBeddy]

Overheating 101.
Overheating can only be caused by 3 things.
1) not enough water flow - blocked radiator etc
2) not enough air flow - too small a radiator, fins blocked by grass seeds etc
3) mechanical issues -water pump, head/head gasket, incorrect thermostat/radiator for the motor/usage.

I'd like to add a 4th, related to number 1.

4) Too much water flow. Usually caused by one or both of the following. People remove the thermostat thinking that will prevent overheating. However the system requires an amount of restriction to control the flow. If this flow is excessive, the coolant will pass through the radiator too quickly and not be able to transfer its heat into the radiator tubes.  Secondly, people will change their front pulleys for a variety of reasons, If the water pump speed is increased too much it will cause the coolant to flow too quickly. See first point about heat transfer for why it over heats.

My input for what it is worth.

Beerbeddy

[Merlin]

Check for air locks (there is 2 bleeders on the v6).I just bought a WH stato with a supercharged V6 for 3K the bloke was told he had blown headgaskets ,it kept overheating. It turned out to be a leaking radiator hose (cost me $9.60 to fix) causing an air lock . .make sure its bled out properly and you should be right.     Cheers Neil

[Sammy]

I'd like to add a 4th, related to number 1.

4) Too much water flow. Usually caused by one or both of the following. People remove the thermostat thinking that will prevent overheating. However the system requires an amount of restriction to control the flow. If this flow is excessive, the coolant will pass through the radiator too quickly and not be able to transfer its heat into the radiator tubes.  Secondly, people will change their front pulleys for a variety of reasons, If the water pump speed is increased too much it will cause the coolant to flow too quickly. See first point about heat transfer for why it over heats.

My input for what it is worth.

Beerbeddy

I tend to disagree, because yes the faster flowing water has less time in the radiator to cool, but it also has less time in the block to pick up heat, so one cancels out the other.

[BeerBeddy]

You are welcome to disagree. But I'm still right!

I've studied thermodynamics and have many examples in domestic and racing practice where I've seen this to be true.

These are two examples:
 
I own a 1930's vintage car. Cooling system is perfect except it runs hot all the time and I cant get the correct thermostat for it. I removed the thermostat and it over heated again but only on highway driving. I made a metal disc with a 25mm hole in it and placed it where the thermostat should be as a starting point to give me some idea if I needed more or less flow. Of course it was slow to warm up without a thermostat but amazingly, it does not overheat and sits right around where it is supposed to be. I have left the disc in place with no dramas since.

I have been crewing for a V8 speedway team for a number of years. We decided to change the power steering set up, in doing this we had to change the pulley sizes and therefore ratios. First heat out we had overheating problems. Realising the coolant was flowing a lot faster because the waterpump was now spinning a lot faster too.  With no way to change the pulleys, we changed out final drive ratios (thank God for quick change diffs) reducing the engine RPM (and sacrificing HP) and the car finished the night OK. Back in the workshop, we re-did the pulley set up bringing the waterpump speed back nearer original and have had no issues since. You must appreciate that these race engines are working harder than normal and cooling is marginal at the best of times. So it appears Beddy cooling systems are not so different.

Anyway, again, for what it is worth.

Beerbeddy