cooling system hassle

[airhead]

This is cracking me up. I have been chasing cooling system issues on the van for god knows how long now, having replaced the water pump, replaced the thermostat, flushed the rad twice, done the head gasket twice, replaced the head and still it continues. As it stands now, I flushed the system yesterday using some coolant system flushing stuff and I bled the system. It's an AAZ engine in an 87 van.

How it manifests itself is you could be driving along grand in town, it wouldn't overheat at all, rad fan would click on and off as normal but take it onto a motorway or put the engine under any sustained load and the temperature starts climbing. When I checked today the coolant hoses were fairly firm but there was no appreciable gain in the coolant levels or it wasn't spitting coolant or anything. The gauge was up at 3/4 and the rad fan wasn't coming on. If I put the rad fan on manually using the switch I put in it doesn't cool the engine appreciably. My reckoning is having the fan on full tilt (and it sounds like a jet engine) would pull the temp down in no time.

When I was flushing the engine yesterday I noticed the rad started to heat up as the engine heated up and the hose from the head that goes off towards the rad was getting warm but the other pipe that goes onto the thermostat housing was stone cold. This would lead me to believe that the water pump may be turning the wrong way, as in I have an AAZ water pump for a serpentine belt and its being driven by a V belt. The other option, and I really hate saying this, is the head gasket may still not be right. Now it doesn't boil over properly but it gets uncomfortably hot, as in it gets up to 3/4 and slightly beyond before I have to pull back. If I turn the engine off when it's this hot it's a pain to restart requiring lots of cranking but it will start eventually and drives fine. There's no change in performance and the engine does perform well. All the belts are tight.

Please help. I'm genuinely at wits end with this.

[MGP]

This sounds exactly like my van when I first got it, the previous owner replaced the head gasket 3 times.
I could drive all day round town and on the motorway on the flat at 50 all day but the first Hill or trying to go up to 55 saw the temp gauge go up.
I flushed the radiator many times including using a flush and a de-scaler it made no difference so i replaced it and all has been well since.

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[ajsimmo]

I think you may both be right. I'd definitely fit a new rad as the standard t3 unit is only just boss of the job. Any flow restriction and it'll struggle to shed the heat. Secondly it's a good observation on the possibility of a wrong water pump. With the original aaz pump (from the car) it runs anticlockwise on the back of the serpentine belt. The van setup (eg JX or KY) with single or double v belt would run a clockwise pump. Worth changing that too.

[airhead]

How can identify if the pump is turning the right way without just replacing it on spec. A rad is already €140. I don't want to spend an extra €60 if I don't have to. Anyway I have the original serpentine pulleys from the engine and the alternator so if I need to I can swap them over. I did replace the water pump already. I just want to make sure I didn't get the wrong one.

[MGP]

Can you remember which side of the serpentine belt the water pump run on? I run the aaz setup on mine and the pump runs on the face of the belt despite it being a smooth pully so it's a clockwise pump

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[airhead]

Well when I got the engine the pump ran off the back of the belt but I've since changed the pump. I just want to make sure I have the right pump though, in case I was supplied with the wrong one.

[Oldiebut goodie]

It depends upon which pump you asked for, surely? You haven't stated what you put on there so we are only guessing.
My 1Y engine came with the pump running anti clockwise off the back of the belt and I changed it over to v-belt running clockwise with a JX/CS pump.

[airhead]

Moreso it depends on whether or not I was given what I asked for. I asked for and I believe fitted a jx pump but I want to double check when I have the coolant drained to do the radiator.

[airhead]

I set about changing the rad today. As soon as I got the old one off I pulled the side off it to have a look. It was full of gunge and half the cooling channels were blocked. The new one was so much handier to bleed than the old one. Just goes to show those flushing agents don't really work.

[airhead]

Well I bled the system fully last night and let the last of the air out of it. Much easier process with the new rad. Left the engine ticking over for a while as I tidied up my tools, heard the rad fan click on and off again, and the rad was fully hot. Drove it into work this morning - a 40km journey - and not so much as a suggestion of overheating as I caned it on the motorway! Temperature gauge sat comfortably just to the left of the LED the whole way in, so I'm delighted! Thanks for the help folks. I think I can say this issue is now sorted.