Ally rad and fans, Radtec, NAR, other?

[TMC29L]

Am taking the E Type to Le Mans classic this year and whilst I don’t overheat here, I haven’t used the car recently on a hot day, the likes of which we had last summer. Don’t want to be in a traffic jam on a scorcher watching the needle rise and rise. It may be fine but….

Therefore, anyone fitted an ally radiator and modern fans to an S3 auto and can say that it’s a worthwhile exersize? I will avoid the eBay Chinese ones and know of only Radtec and NAR. Any recommendations for either or a different brand?

Cheers.

Dominic

[vee12eman]

Hi,
I don’t have exactly the car/situation you describe, but here’s my experience. I bought an Auto S3, which was missing the radiator. I waited and sure enough, found a manual gearbox (5 Speed) so I bought a new, aluminium radiator for the car, manual version without the Transmission cooler. It was from NAR, quite a few years ago, bought at one of the Stoneleigh shows and was a little cheaper being a scratched example. I bought modern fans from V12S in the USA, my original shroud was probably still attached to the missing original radiator. A year or two later, still having never started the car, I emigrated to Australia, bringing the car with me. When I finally fitted everything, I used a modern copy of the Lucas relay, which immediately fused closed. I then re-wired, I think the wiring diagram I used is in the knowledge base still. The new wiring used two Bosch relays, one for each fan and I added a modern blade type fuse.
The car has since run, in traffic, at ambient temperatures over 40 degrees C with no problems at all, but a proviso is that the engine was also cleaned externally and internally and that certainly helps as there is no silt in the engine, something the V12 is prone to if neglected. Ten years on and I changed the coolant, which was as clean as the day it as installed, though the car is low mileage since rebuild.
Unfortunately V12S is no longer active as far as I can see, but the aluminium shroud is relatively simple and the fans are just the largest that fit. The only problem I have had other than the relay, is that the aluminium drain plug stripped a thread when I changed the coolant, requiring a new, stainless steel plug with a helicoil insert, probably a good upgrade in any case.
Hope that helps.

[Direwolf]

Hi, l live about 1 hour south of Le Mans and l recently changed my rad and fans on my S3 manual 2+2 with AC.

Over the winter l had noticed it was leaking coolant and l could not see problems with the hoses or connections.
I also had the original fans so l wondered about changing all to confirm it would be reliable. I had not overheated here even though it can be very hot weather but it did run very hot and after stopping it would occasionally throw out some coolant.

I bought a Radtec complete assembly with a new header tank which was great and not difficult to fit other than getting the condenser off its mounts and carefully resting it on the inside of the grill with the hood fully vertical (front wheels on wooden blocks and detach bonnet stay). The alu rad looks great but is mostly hidden when you put the top cover back in place. I would not use any other supplier than Radtec or NAR who are also very good.

I think making sure your thermostats are correct and opening properly and in association with the temp sensor and fan switch, also the water pump is running well, if these are good and your radiator does not leak it should be ok.

When l first got my S3 it was running very badly and seemed hotter than it should be, after seeking help from better people than me it was found to be the ignition timing.

I am interested in entry’s on the forum l think from Aus or South Africa where they discuss putting an inline electric water pump so when the engine has been running on a hot day and is stopped the coolant can continue to circulate while the fans continue to cool for a short while so as to help reduce temp build up of water in and around the engine. I know the engine was designed to be ok with this but l can’t help but think a 50year old engine could do with a break from these high temps after stopping (l am not sure if the original water pump would have to be removed to allow flow when stopped). See you at LMC.

Bob

[TMC29L]

Thanks for the advice Bob. I think the Radtec is the way to go for me.

[mgcjag]

Please note...you dont have to quote the entire post including photos when you reply...it just uses up server space....iv deleted it.....thanks....Steve

[MarekH]

Running the fans on their own does almost nothing to help you post shutdown. The temperature in the cylinder heads continues rising and/or is largely invariant to the fans if no water is circulating. All you create is a reservoir of cooler water in the radiator. However, if you turn the engine back on for 30 seconds or so after a few minutes, you can swap this pool of cold water for the hot water in the cylinder heads and thus you won't need any fancy electric water pumps, just a bit of patience.

See https://forums.jag-lovers.com/t/solving ... ple/377151

kind regards
Marek

[lowact]

I would be concerned that a sudden step change in temperature might exacerbate the issues you are trying to avoid?

[Series1 Stu]

I wouldn't worry about that. Its not a massive thermal shock.

There will be a small benefit from running the fans after shutdown in that it will be pushing cooler air around the engine compartment, but not a massive gain. It certainly won't directly cool the cylinder heads.

Regards

[MarekH]

Worried about thermal shock?

In the example quoted, coolant temperature drops 12'c in 45 seconds and radiator temperature goes up 45'c in the same time. Do you really think that's a problem?

Now consider what happens every time you start your car because you already do something sort of similar every day.

Consider that if you start from cold, the thermostats start closed.... water circulates in the bypass until it's 82'c and when the thermostats open, your engine coolant is hit by virgin cold water, not lukewarm cooled down water. Granted, the effect isn't as great because water bleeds through so the changeover isn't as instantaneous, but if this worries you, then just run the procedure with only half of time delay, so the fan runs half as long before you run the engine.

That's pittance though compared to combustion temperature changes. When you gun the works, the exhaust gas temperature goes up to ~650'c in the time you go from 0-60. Coolant wise, a massive volume of water is pumped into the cylinder heads if you spin it up to the red line and the radiator temperature can go up 20'c in ten seconds. That's a tad more thermal shock than pumping water through at idle rpms and only having a combustion EGT of a constant ~130'c.

kind regards
Marek

Graphs:=
Here I appear to have gone 0-60 in 7.7seconds and that's including a leisurely 1.3 second gear change from 1st to 2nd. This is the data between the two vertical grey lines where I drop the clutch at 1500rpm and rev it to 4800 (and then beyond). Ignore the bit about the car continuing to accelerate past 60 as I'm obviously not on a public road.(Middle graph shows speed in green.) The lower graph shows the coolant at the bottom of the radiator (dark blue) has moved up 16'c in 7 seconds. I'd suggest this is more thermal shock than cooling for heatsoak.

0-60 shock2.png (84.06 KiB) Viewed 1731 times

Interestingly, aside from the agricultural 1.3second gear change, I appear to have been pretty gentle off of the line in first gear - the engine is only starting to breathe at ~3000rpm. This car could accelerate much faster if it were simply held at or above 3000rpm for longer - but I wimp out at 4800rpm and spend 40% of the time at low revs below 3k.

[jagwit]

Both my S3's are running with alu radiators made by a small radiator service outlet in a small town called Knysna in South Africa...

Both cars are running with vacuum advance fed directly from manifolds. This results in full vacuum advance being applied at idle (and under all very light throttle rpms) which in turn helps the engine idle / run more efficient and hence generating less heat for the radiator to get rid of.

Both engines also have my version of the Lutz mod (choking the front two block - head coolant ports, forcing more coolant to the rear of the block).

Both engines also have 74degC thermostats with matching 72-67degC fan switch (Echlin FS155).

The OTS has original fans and has 0 cooling issues in the hot South African summers. The 2+2 has VW fans but also has aircon.

Both cars typically run on or just below the N of Normal.

[lowact]

I was going to do the Lutz mod also, till I learned that for the last V12 (X305) Jaguar eliminated the rear two head coolant ports and the water rail entirely?

[MarekH]

The interesting question to ask is whether Norman's mod will work just as well if it reversed front to back, as this is effectively what a "one-exit" x305 water system is. Having said that, unless the part number for the cylinder head is identical, it may be that the x305 has different water passages inside the head to accommodate the desired flow for just one water exit.

For those who didn't realise, Norman's mod was originally developed for the 6 cylinder cars and then transported onto the v12.

kind regards
Marek