Strange Overheating.

[Ben2802]

Hi all. Couple of issue with the gv but the most concerning and expensive one is overheating. Took the car on holiday towing a caravan last year and every time we went up a slope it would start to get hot on the flat was fine. Eventually made it to site and all was fine during the 2 weeks and going up hills wasn’t an issue so I assumed the overheating was due to the extra strain pulling the van. I decided to ‘ breakdown’ and get recovered home instead of doing anymore damage to the car fast forward today and I’m taking my daughter and 5 others to there football match, half the team, and going along the motorway at 70 and the temp starts going up again, windows open heater on full and drop the speed to 65 and it starts to cool down. I do have a new rad in the shed that I was planning on changing tomorrow as I’ve notice a small leak in it and not a fan of rad weld. I’ve never heard the fans kick in so plan on testing them while I have them out. When I turned up on holiday last year the chap that greeted us said he heard the fans working but until I see them working myself I won’t be 100%. Any comments would be great as I have the return trip to do.

[bignev]

Hiya! 

Definitely a good plan, and also give it the system a flush out with a hose pipe, i would do it just before you swap the rad personnally.

 

There is a good method on the forum from Qinteq somwhere, as I had a petrol not totally familiar, but essentially hose in the header tank, engine running to pump it round, and bottom rad hose partly of for it to escape and rinse through the system.

 

Before that though, as you say, check the rad fans run, but should not be relevant at 70mph.

[Ben2802]

I agree that the fans shouldn’t come until there isn’t enough air passing the rad. Don’t think it’s the water pump as it would be an issue all the time. I usually start the engine 5/10 minutes before I leave for work just so everything has a chance to warm up a little as I’m only a couple off minutes off the motorway with a steep hill to start the trip to work. I’ll have search for post about flushing the rad and probably do that. Thanks for the reply.

[soupstone]

First done it whilst towing, now does it when solo and full, I'd suspect the radiator is silting up. 
Had it on other cars, get it up to temperature, do something to make sure the fan wont start spinning  (jam with something, it'll only take a few seconds) and feel the radiator, top and bottom. Will be cooler/cold at the bottom if it's blocked. 
Radiator hose would be hard to press as well, due to the pressure.

[SpAwNtoHell]

If is an auto transmision, that can contribute to overheating...obviously with a au gearbox is more strain when towing on the oil of the gearbox and is cooled through the lines of the radiator but the fan should kick in then very fast.

[dave62pb]

With Voyager autos, t recomends to tow in 3rd , i tow a caravan and at first had the same problem, what I do is run in 3rd when on A & B roads and up hills then when cruising or on long flats shift into D,  make sure you have the correct coolant and rad is clear, I did have to change mine as it blocked and sprung a leak

[soupstone]

Got rid of my voyager because mines was no good for towing. It may have been an underlying fault/issue with the gearbox. I'd had the fluid and filter changed nd it made no difference. 
  Even with an empty towavan on the back, it would kick down too readily trying to maintain 50 on the flat. 

I got the temp creeping up when going to Cornwall, up a couple of the big long climbs, but it settled again once on the flat/downhill. That was with 1600kg on the back. 

 

[BumBle02]

It,s a good chance that it is the fan relay located between the rad and grill it looks like a square box with round spots on it they do go and the fan we not come on.