960 getting hot (still)

[IainG]

Hi
Just reread your thread.
I know you have changed the thermostat a couple of times. Is it worth doing a test and run without the thermostat for one trip just to see if there is any difference. I know it will take longer to warm up and will probably run cooler most of the time, but would be interesting to see if it makes a difference at higher loads.
I had a thermostat that didn't open fully and caused similar, but as you have changed it a couple of time should not be your case. Just curious to see if there is any difference. And if the thermostat could be causing a restriction to flow?

Iain

[Laird Scooby]

Originally Posted by IainG

Hi
Just reread your thread.
I know you have changed the thermostat a couple of times. Is it worth doing a test and run without the thermostat for one trip just to see if there is any difference. I know it will take longer to warm up and will probably run cooler most of the time, but would be interesting to see if it makes a difference at higher loads.
I had a thermostat that didn't open fully and caused similar, but as you have changed it a couple of time should not be your case. Just curious to see if there is any difference. And if the thermostat could be causing a restriction to flow?

Iain

As you rightly point out, he's changed the 'stat a few times so it shouldn't be the case but it's possible - running without a 'stat would have to be a "last resort" test though. The natural restriction of even a fully open 'stat creates a thermal mass of coolant in the head to ensure even heating/cooling of the head, without it hot spots can be created which can cause warpage.

Something occurred to me overnight though - what sort/colour is the antifreeze? The car would almost certainly have left the factory with ethylene glycol (blue/green) antifreeze. If some clever clown has replaced it in the past with the red (or purple) OAT stuff, that's probably the cause of the problems.
Unless the system is meticulously flushed and cleaned of all traces of the old stuff (which is near impossible without renewing every component in the system including the engine) the OAT and ethylene glycol will react and form a gel.

This will cause blockages in the cooling system.

It makes me wonder if the previous owner changed to OAT from ethylene glycol (or a garage did it) and the system wasn't properly flushed (even then there's a high chance of blockages) and the car started to overheat. Could be the real reason it was up for sale in the first place!

[3VOM]

Dishwasher tablet time? Never done it myself but you put a plain dishwasher tablet in the coolant system and run it to give a flushing round. Obviously drain and rinse out the cooling system after to remove any unwanted bits and fluids. It'll be on the internet somewhere.

[Laird Scooby]

I've done the dishwasher tablet trick a couple of times, works fairly well. Also once with a very badly blocked cooling system, i used caustic soda - the sort sold in DIY places, supermarkets etc for unblocking drains and the like.

It gives two mix ratios on the bottle, one is for "normal" cleaning and the other is heavy duty. The cooling system i was working on held about 10L so worked out to be the "normal" duty cleaning mix.
I flushed the system, half filled the system, added the caustic sod and then topped up with water and ran the engine until up to normal temperature. Let it cool overnight, topped it up in the morning, ran it up to normal temperature again then let it cool a bit before draining and back-flushing until the water ran crystal clear.

Ran it for about a week on plain water (no antifreeze) to make sure there were no leaks, back-flushed it again, drained it out again, refitted all hoses etc and added 5L of antifreeze and topped up with plain water. Warmed it up to normal temp, let cool overnight and topped with plain water the next morning.

Problem solved on that one! Heater was incredibly effective afterwards as well!

One thing to note though is if any components like the heater matrix, radiator or similar are a bit suspect, the caustic soda will find the leak and usually make it worse. As long as the system is basically sound, it will work fine - as it did for me.

[Chooch84]

I'm guessing depending on the brand of dishwasher tablets you go for it'll either leave a lasagna stain or make the coolant tank look cloudy... :-\

[barkster1971]

You can easily add a water/meth spray that will cool the radiator by moving the headlight washers to spray the radiator and add aquamist to the intake. Also have dual rad fans and remove the grill when towing. Have you still got the original airbox? I take it you've thrown the crappy lower part/flap away?

[rogerthechorister]

The system was first pressure flushed forwards and then pressure flushed backwards before the first change of radiator (for another standard one). No sign of sticky stuff in the water hoses. No, I have not tried radflush or a homemeade equivalent - too worried about heather matrix dissolution! I always run the hideously expensive Volvo coolant. The van is a little light one - an Abi Ace Airstream - about 800 kg in running order. I have tried a different instrument cluster. In normal running the needle is exactly vertical and never moves - at steady speeds of up to 130. When the problem manifests the needle heads for the red - I have been within a whisker of it actually being in the red by dint of inadvertence. The car cools down in under 30 seconds if I start going down hill, so it is not in practice possible to get the gauge moving, whip over onto the hard shoulder, leap out, lift the bonnet, and get a reading (and then explain to the nice Ossifer).

I am hoping to make a test run next week or the week after.

[rogerthechorister]

960 retrieved from Tim the Mecco today. He's done a lot of work and his bill was quite reasonable. 100 amp feed direct from battery to split charge relay - so now the caravan fridge actually works while towing (when I have a portable fridge plugged into the cigar lighter, which used to drop the voltage to the split charge relay) and it shouild help the charging of the van battery while towing, too. DO88 rad installed. Inarf big Brian. Now TWO atf coolers, the huge Mishimoto and a Transaver, mounted on proper meccano not cable ties, and the pipes much tidier. Monster 4 air-horn setup. Undertray modified to clear the rad and atf coolers. New good oil, new good Volvo coolant, and new good super-dooper atf (Dexron III I think) the Volvo stuff being unobtainable.

Test run (with van on) at 70 up a hill that used to have the needle headed for the red at 60 - needle steady as a rock. Gearchange much better too.

Some tidying up to do underneath (some protruding bolts to cut off and a shield to manufacture for the atf coolers, I don't want a stone through them).

The only snag so far is I drove off with the remote for the van motor mover still on the drawbar cover, so that is lost, but I can get a pattern replacement for £75.

Next step the remedial paintwork and fix a rusty housing for the bu88er alarm - that will be another £500.

Then get the ALD inserted so that I can tow out of muddy fields.

And FINALLY maybe a gas conversion and upgrade the sound system.

[rogerthechorister]

Went the 60 miles to Deal and back this weekend, running like a bird, gearchange responsive. Fridge feed not working although it was when I left, so I may have some rummaging to do with a voltmeter.

I may need to tighten my Al-ko, I was feeling some sway as I got to 70 (which I could not before so it is progress of a sort) and I notice that I am earing the outsides of my front tyres, but that might just be that I am an elderly hoonigan.

[Laird Scooby]

Originally Posted by rogerthechorister

I may need to tighten my Al-ko, I was feeling some sway as I got to 70 (which I could not before so it is progress of a sort) and I notice that I am earing the outsides of my front tyres, but that might just be that I am an elderly hoonigan.

I think the two could be linked, especially if the back of the car was fairly well down dragging the van, especially if you've got lowered springs on the car.

Unless i've got things horribly wrong, the way the suspension works on the front means that if the front is higher than normal, you get more positive camber which will be exaggerated by shorter/lower springs.
That would put more loading on the outside of the front tyres or it could simply be down to alignment/tracking with too much toe-in.

The other thing you could try if the front end is high when the van is attached is a pair of Grayston Coil Spring Assisters.

http://www.ebay.co.uk/itm/One-Pair-O...kAAOSw8cNUSQ6O

Those should be the right ones for the standard springs, in the listing there is a link to Graystons site to double check. If you do have different springs you may need different ones, again that guide would help.

Out of interest, when did they raise the speed limit to 70mph for towing on a dual carriageway/motorway?