13 replies to this topic

[I could eat a horse Haha]

Constantly overheating engine requires further cooling than the current setup can give.

Going to plumb in a small second radiator off a motorbike so the question is does anyone have any ideas as to what the best way to plumb it in might be?

My first thoughts were to take the hose from the top of the thermostat housing into the new rad then out into the existing rad.
Keeping it in series so the fluid flow must go through both radiators?

Cheers All

[dklawson]

I've never done it myself. However, fitting an aux radiator is fairly common in the U.S. and apparently in OZ.

Take a read of the information in this recent thread. Hopefully it will provide some useful information:
http://www.minimania...2/msgthread.cfm

[I could eat a horse Haha]

Cheers very useful.

I guess i just need to decide if I fit it in series with the current rad or in parrallel.

My water pump has the take off on it for cylinder head bypass which I am not using. Could feed from this to the auxiliary rad then back into the lower hase on the main rad.

I fear this may require some testing of the bodge it and see variety until I get it working

[Pooky]

Why is your engine overheating? Unless you've got some 1460 Turbo engine and do a lot of racing in Dubai I don't see why you'd need extra cooling especially to the extent of fitting an auxillary radiator. If you have a fault that is causing your engine to over heat, putting in another rad is not solving the problem. If you do have a heavily tuned engine maybe an oil cooler would be something that would be easier/more effective but you'd need to fit an oil temp gauge to find out if you need one.

What engine are you running, what are your symptoms of overheating and what have you done to try and solve it?

[bmcecosse]

Fit a 74 degree stat - and the earlier smaller waterpump pulley. And - flush out your rad and engine with a hose. Best place for a second rad (which you should not need) - is on the heater circuit.

Edited by bmcecosse, 22 June 2010 - 01:23 PM.

[Cooperman]

Fit a 74 degree stat - and the earlier smaller waterpump pulley. And - flush out your rad and engine with a hose. Best place for a second rad (which you should not need) - is on the heater circuit.

Agree absolutely. A Mini should not overheat, even a very powerful one. In fact, you don't even need a special radiator. I run my Cooper 'S' which has 115 bhp with a standard Cooper 'S' radiator and a thermostat blanking sleeve and it usually runs at around 80 deg C and that is with a very low final drive, (3.9:1), spotlights and a sump guard, plus a 13-row oil cooler. I sometimes use the manually-switched aux fan, but only in slow/stationary traffic on very hot days.
As 'bmc...' says, check out your system, flush it through and/or fit a new radiator and a 74 deg stat. It should then be fine. If it's not, maybe your timing is retarded which will cause overheating and/or you are running too lean a mixture.
For an aux radiator, I've seen a heater matrix used and fitted in-line in the heater ciruit and located behind the grill next to the oil cooler.. Then you have, effectively, 3 rads, the heater itself plus the aux plus the standard one.

[I could eat a horse Haha]

It is a 1380
stage 3 head
286 cam
11:1 CR.
Megajolt Ignition. (Timing map is spot on)


It has a 10 row oil cooler + mini spares super cool 2 core radiator. Both brand new.
The engine was also a recent new build.
Cooling system is very clean. The block was chemically cleaned. Coolant is still a very clear pink colour.
Has a thermostat blanking sleeve and new water pump. Also has a manually operated electric fan to assist the engine driven one.

The engine is about 6 months old and when it was running in the winter temperature was fine. Now the weather has warmed up it goes into the red after about twenty minutes of driving.

The engine is running slightly rich so can discount that as a cause.
The gauge could be faulty but it is clear that the engine is too hot. It starts to smell and begins to smoke. Never let it get all the way into the red before turning off to let it cool down.

It runs perfectly other than being too hot.

May try some water wetter in first and have a double check for any air locks

Edited by I could eat a horse Haha, 22 June 2010 - 09:38 PM.

[I could eat a horse Haha]

Anyone any ideas as to why this is getting hot?
Everyone seems to think it shouldnt generate this much heat.

Ta

[Jordie]

i never had cooling issues running a 1310cc modified turbo motor without a heater at all. I used a 2 core radiator from mini spares and a 13row oil cooler. The heater matrix was taken out and the hoses joined inside the engine bay. No extra fans, just the 2core rad and thermostat sleeve.

I cannot think what would make the engine run that hot if you say you have these new parts fitted and the timing/fueling is right.

[Shifty]

Is the fan on the right way?

[Cooperman]

Could it be that these 'fancy' rads don't actually do the job right?
Personally I've always used the standard rad, which was fitted to all 998 and 1275 cars. Originally the Mk 1 'S' had a better rad than the 850, but they were all standardised on the 'S' version a long time ago.
The only mods I've used are a 6-blade (Export) fan and a thermostat blanking sleeve. The blanking sleeve is really to take away the risk of a stat sticking closed on rallies, and a 74 deg stat is probably as good.
The fan on the wrong way round will cause a loss of around 20% in air passed through the rad, so 'Shifty' could well be right. It's a basic error which many make. I've even seen a 'works' rally car with the fan on inorrectly, so don't feel bad if you've done it.

[bmcecosse]

FIT THE SMALL PULLEY! And if that doesn't work - then yes try the export fan. Is the 4 core rad not THE one to have ?
Have to say though - if it's producing that much heat - the block may be porous - always a risk with these big bores.

Edited by bmcecosse, 23 June 2010 - 09:49 PM.

[I could eat a horse Haha]

yeah fans are on the correct way round.
Pushing through the rad into the wheel well. The electric fan on the other side of the rad is the puller type so the two work together.
I may have the smaller type pulley from the original 998 engine somewhere - will go look. Worth a try.
The rad I have is the minispares supercool 2 core

Edited by I could eat a horse Haha, 23 June 2010 - 11:22 PM.

[I could eat a horse Haha]

Tried the smaller pulley. It was slightly better I guess but not enough.
Will try the old standard radiator again at weekend. It is also virtually new so see if it makes a difference.

Also the second rad should be here. Using an alloy heater matrix from a rover 75. Only about 9 inches by 8 inches in size so nothing massive.