Supplementary fans

[OneCarefulOwner]

My cars run at a good temperature 90% of the time, as even with modern traffic I can usually keep moving enough to maintain airflow and on those occasions I can't, the stock fan tends to keep up. However, sometimes (such as the Thursday prior to the NEC) I get stuck in some of the gnarliest London gridlocks known to man, and unsurprisingly the Austin Allegro just wasn't designed to cope with such conditions. So I'm thinking of adding at least one supplementary fan.

I know where, I know how to mount it, whether it should be set to push or pull, all that stuff - but the market for such fans is huge, with prices from £20 to £200 for what, to my eyes, look like very similar products. Gone are the simple days of the 60s & 70s when all you needed to know was Kenlowe...

Has anyone got any recommendations of vendor, brand, style (flat vs curved blades, for example) etc.?

[JPB]

If this were just about any other BL product of a certain age, I'd be recommending Pacet by now, but the Allegro's efficient, modern crossflow radiator with its factory electric fan should be every bit as effective at keeping itself cool as anything more modern so rather than masking the symptom, I'd tend to investigate the cause of the original problem.

Has the radiator lost a significant amount of matrix to erosion by insects and roadborne debris in general? That would make it run hot in traffic.
Is there too great a quantity of MEG in the coolant? 30% and not a drop more will be ideal but if it's been added in a greater concentration then that'll add roughly 2C per 5% over the 30 since too little water reduces the water jacket's ability to soak away heat when there's no air to keep it down; the exact symptom you've reported.
A series, like many simple OHVs of a certain age, tend to run their oil hot and their coolant under its most efficient temperature though that's mote often observed in North-South installations with a fixed fan.
If this is an E series you're running then does it definitely have the right radiator? E4s do tend to creep up a fair bit more in traffic and not every radiator specialist knows the difference between the types so they can end up with the wrong one.

In either case, check the pressure cap as a weak spring there can cause an engine to boil its coolant at a much lower temperature. Either E or A will safely run a 15Lb cap on the EV in place of a 7 or 13Lb one, that too would keep it cooler but don't waste the cash on another fan. The original one is - when working correctly and cutting in & out - every bit as effective as an aftermarket device of equivalent size.

[Mitsuru]

To add to what john has said, time can also take it's toll on the fan
and it's motor as well. Even though it may be clicking in and out, it
might not be working properly due to bad carbon brushes, or fouling
between the fan and the casing. For that matter whats not to say
that the coil might not be faulty?

If you expect to be stuck in traffic a lot, there might be a little thing
that won't cost you anything but it would depend on the car as I
don't know the allegro. Some cars have rubber weather strip along
the back of the engine bay. Removing it will allow the heat to
escape the engine bay more quickly!

Although it will not cure your heat problem it might buy a bit more
time to find the fault and fix it.

[Luxobarge]

As above, +1 for sorting out the standard car's cooling. These cars aren't really that old, and were perfectly capable of cooling themselves indefinately in stationary traffic when they were new, so I agree there's possibly something not quite right about your current set-up IMHO. I think John has most of the issues covered in the post above.

He's right about the A-series, I run an A in the Midget, and have added an oil cooler for additional cooling (as mine's fairly well "breathed on") rather than any additional water cooling, and it's absolutely fine. If mine had been an engine in standard tune, I'd have just made sure everything was AOK including a new rad, and left it at that.

What engine are you running out of interest, and is it modified in any way?

Cheers!

[OneCarefulOwner]

The problems have manifested primarily in my 1500 E series, which is entirely unmodified. It has the right radiator, it's been extensively flushed & refilled accurately recently by my local classic-friendly garage (who're still washing away the detritus that came out!), and the fan appears to be functioning at the proper speed & temperature as far as I can tell. I'll check the radiator cap, but as the fluid levels seem to be fairly constant I don't think I'm losing much via pressure relief.

To be clear, this isn't a couple of minutes stuck waiting for a gap to open up - it took me an hour & a half to travel 10 miles, almost 30 minutes of which was progressing 400 yards through Hammersmith where some ignorant schmo had decided that his delivery van didn't need to obey the "no deliveries at this time of day" sign & blocked the narrow bus route solid just around the corner from roadworks that were causing even more contraflow hassles. Queuing to get into the exhibition centre after running up the motorway also displayed a sharp upward swing in the temperature gauge but it soon settled as we continued making headway regardless of how slow it was - whoever decided that classic cars needed to sit in queues while entering event sites needs slapping!

I'm not really overly concerned about this car though; it's my other daily estate, which has been breathed on a tiny amount and is likely to see a few more little "usability tweaks" in the future. Would an oil cooler make much of a difference to the overall operating temperature in a queuing environment?

[suffolkpete]

If the fan motor comes apart, then I'd clean up the commutator in a drill chuck with a piece of emery, clean out/undercut the segments and lubricate the bearings. Are these fans polarity sensitive? Has it been wired up wrongly so it's running in the wrong direction? I'm sure the standard setup is more than adequate if it's in good nick.

[Wicksy]

I tend to agree with the" sort the rad out" posts - the temperature on the day in question was around 8 deg c and an agro should cope with that without any tendancy to overheat however long you were stationary unless the stat is sticking closed. I made the same journey in my Priness 2 which has the 6 cyl version of your engine and although the fan kicked in, the temp guage stayed at just below normal.
I think it is very possible you simply have a partially blocked rad and should get it re -cored or buy a new one.
If you have easy access to the rad you may be able to detect by hand the cool spot in the rad which signifies blocked tubes - a good garage should have equipment which gives a heat gradient readout which again shows up the cool spot and confirms the blockage; that may cost you more than a replacement rad though

[Minxy]

In case you needed another 'echo' I agree with the above sort the problem don't mask it.

[TerryG]

Just as a side note, if you had a load of crud washed out of your radiator it is almost certain that some of the passageways are still blocked. You could test it with one of those laser thermometers and check that it is getting evenly warm.

[OneCarefulOwner]

I think Terry's got a point there.

I'd also like to remind folks that unleaded burns hotter than leaded did, meaning operating temperatures can rise beyond original expectations. And if all engines are designed with adequate cooling, supplementary fans would never have been invented