Radiator sizes and qualities?

[boatbuilder]

So I'm just back from a thousand mile road trip and noticed a cooling issue on long journeys.
I have a 1.9d non turbo AEF engine with stainless 32mm coolant pipes and mostly new rubber pipes and a new radiator fitted.
The problem is that on long journeys the temp needle goes up to maybe 3/4 or slightly more on the gauge. When I turn the heater on, the needle goes back to the left of the led within about a minute. When I turn the heater off, it inevitably goes back up again to 3/4.
I thought it may have been a thermostat issue so I took it out completely but that has made no difference.

So now I'm wondering if my new rad simply doesn't have enough cooling capacity?
It's one of the cheaper rads with the round tubes and aluminium fins in the radiator core. The original rad was thicker, had heavier copper fins and more numerous and flatter aluminium channels for the coolant running through the core.

What do you think?

The old rad had some soldered repairs from previous owners and it has another hole and there is a piece of steel along the bottom of the rad that's rusted through so I thought it best to replace the rad completely.

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[colinthefox]

From your description, it does look like a cooling capacity issue.

When I replaced my rad, I was offered a 25% uprated capacity unit at the same cost. A no brainer. We've given the van some real hammering recently, and it has never shown any sign of overheating, just a slight increase in temperature on the longest mountain climbs at full throttle. I think it was Valeo or Hella Behr.

[Highroller]

I believe that there is a 43mm thick radiator fitted to diesel and the 2.1 petrol engined vans. The 1.9 petrol was a 38mm radiator. It may be worthwhile checking that you have the larger one. I also read in one of the threads that if the cardboard cowlings are missing from the sides and bottom of the radiator that this can make a big difference on long runs. One last thing, people with the AAZ conversions seem to report that they run that wee bit hotter than normal but I don't know if it's the same with the AEF.

[boatbuilder]

I'm missing the baffles as well... not sure if they would make that much of a difference? I'll try fitting baffles and see what difference it makes...
My rad is a non branded one, cost about 95 pounds...
Looks very much like this one...
http://www.ebay.co.uk/itm/272768451893" onclick="window.open(this.href);return false;

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[RogerT]

I had a diesel type radiator which I think was original, but was clearly quite choked. Baffles made little difference but recently replaced my rad with another identical from BW, pricier that that eBay one, but I now have very stable temps. I also have no leaks, a new thermostat which also came fromBW and seems on looking at it to allow more flow through it, and baffles, so I couldn't swear that any one thing solved my heating probs, but I'd put money on it being a good radiator allowing plenty of cooling. I've also noticed that going down a long hill, my temp stays up more than it used to, which could maybe be put down to a new thermostat closing sooner so keeping the heat in the engine. I'd suggest you try to sell your eBay rad and invest in the thicker one. I'd guess that flatter tubes within it gives more cooling area that the round tubes of the cheaper one, so it may have more than the 30% extra cooling than the increase in its thickness suggests.

[boatbuilder]

I think you are probably right there...confirms what I was thinking...

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[CJH]

I took the radiator out of my 1983 1.9DG-powered van last night, and now I'm confused about the available sizes. Being an 'early' watercooled van, I half expected the old radiator to be the thinner 34mm type. Since I'm upgrading my engine to a 'new' 2.1 I thought I'd fit my new radiator, both to make sure all the sludge and silt is out of the system, and to increase the cooling capacity to cope with the 2.1.

My new radiator is one of the EIS models that a few of us bought when one of the major parts suppliers had a batch of them cheap a couple of years ago. It measures 44mm across the fins, so I was confident it was one of the 'bigger' ones. It has a brass bleed screw, and the lugs at the top seem to be the right distance apart, so it all looks good.

But the one I took out is bigger still - it measure 62mm across the fins. The fins are much tougher than they are on the new radiator (copper? versus paper thin aluminium). It doesn't leak, but is pretty rusty in places. I'm now wondering whether I'm doing the right thing in swapping it. Will I reduce the cooling capacity because the new one is thinner, or will I improve it because modern aluminium-finned designs are better than the old copper ones?

But my main question - where is this 62mm radiator from? Is it the original radiator from my van, or has someone replaced it with one from a different model? And why don't I ever see a 62mm radiator mentioned in these radiator threads?

P.S. My old radiator has the VW logo moulded into the plastic body.

[Oldiebut goodie]

Did the SA vans have the even bigger one?

[CJH]

Did the SA vans have the even bigger one?

That's worth checking up on. Will spend a bit more time on that later - initial searches just bring up lots of links to the 44mm version made by Hella SA.

[CJH]

I've found reference to a radiator designed for use in warmer climates, for towing, or for vehicles with air conditioning. Sounds like it might be a higher capacity radiator. But the part number (068 121 253 E) seems to bring up all the same links as the other variants, as though none of the manufacturers distinguishes between them.

Is it possible that the 44mm versions available now are in fact more capable than the originals, due to a switch to aluminium fins, or is that just wishful thinking?

[CJH]

I dropped my old radiator off at a local radiator specialist, for a pressure test, a flow test and a chemical clean out. On further inspection it appears to be only the top and bottom plates that look rusty, so if it passes all those checks I'll probably blast the fins clean with my air line, and maybe give it a fresh dusting of matt black paint, and then put it back in the van. I'll keep my new one on the shelf for a rainy day.

I did a quick bit of googling, and I think the idea that a new aluminium-finned radiator might be better than an older copper-finned model was just wishful thinking. No sign of a part number on the old one unfortunately.

[Oldiebut goodie]

Looking at your link there are numerous other manufacturers for other vehicles listed amongst the analogues tab. Interestingly upon checking a couple of random part nos the dimensions come out at 34mm x 568 x 430. Without checking a lot more they appear to be the thin ones unfortunately but handy to be aware of.
You must have had a 'goodun' from before vw started counting the pennies as the price of copper rose in 1980's.

[CJH]

You must have had a 'goodun' from before vw started counting the pennies as the price of copper rose in 1980's.

Quite possibly, but everything I've read suggests they started with the thinner ones on the T25. So as my van is a camper conversion done by a UK company from a new panel van (without air con) I'd be surprised if this is the radiator that it left the factory with. Anyway, it'll be interesting to see if it comes back with a clean bill of health.

[Ian Hulley]

Our temperature gradually crept up over a few years and swapping the (perfectly good, non-leaking) radiator solved it instantly.

Ian

[CJH]

Sounds like it may not have been 'perfectly good' after all. Maybe it was gradually clogging up. That's why I've gone for the flow test and the chemical clean, but they did say that if the flow test shows it's too far gone then the chemical clean won't work. But if the flow is OK, then the chemical clean should ensure it's as good as new, and should ensure I won't be putting silt and sludge into my new engine.

But I take your point - unless I'm completely happy with the diagnosis then I'll probably just go for the new radiator. I'm just keen to not discard a radiator that may be perfectly good and may be better than anything I can buy to replace it.