Cooling overhaul

[bob-bobberson]

I recently developed a coolant leak on my Chim and have narrowed it down to the rad (I think). Massive puddle underneath it and the pipes leading in seem to be in good nick, nothing obvious on the radiator though aside from the attached nicks on either end, I guess it could be the core damaged elsewhere that I can't see.

Anyways, I was going to take it to a specialist to get fixed - is it still the consensus that repairing an original radiator is better than buying a replacement aluminium one?

While it's all out I was going to replace all the pipes with silicone ones - are the ones from ACT still the best option? Also I'll do the thermostat too but is it worth checking the water pump? I'm unsure if it's a metal or plastic impeller as that used to be a weak spot on BMW's a while ago so it could be worth doing too

Cheers

Edited by bob-bobberson on Saturday 21st January 15:51

[bob-bobberson]

Belle427 said:

Ive read mixed reviews on Aluminium but have no direct experience so will wait for someone else to comment.
If it were me id try and get the original repaired, add the silicone hoses from Act and maybe put in a new thermostat and leave it at that.
There isnt much wrong with a standard cooling system in good condition.
Id leave the water pump as it may be original and better quality than most of the junk available these days, just check to see if there is any noticable bearing noise or play in the shaft, and indications of any minor leaking.
Also make sure both your fans kick in and actually work as sometimes this can go unnoticed.

Thanks. My cooling was, up until recently, spot on TBH so yeah it's just fixing for the long term.

Good point with the fans, I will check. I was going to fit the fan override thing from the TVRCC pages too as it seems simple to do and it's nice to have an option for being stuck in heavy traffic in the summer months

[bob-bobberson]

Belle427 said:

There is a simple method for fan override but it depends how far you want to get into it.
Behind the radio there is a white coloured connector with a green/pink wire in it, short this to ground and the fans will run.
You basically run a wire from this to a switch and the other side goes to a ground.
You can fit a switch or utilise the dash lights off button if you don’t use it, you would need to connect the wires together that you remove from it for the dash lights to work.

Didn't know that one, thanks - much more simple than the other method, i'll check it out

[bob-bobberson]

ez64 said:

No need for fan override if your cooling system is sealed properly. Silicone all the hoses including the ones going to the heater core and the ones under the dash. Ali radiator and using as a daily without any issues in any weather or stop\start, if you overheat you have a leak or air in the system. The only thing I did differently on my pre face lift is move the registration plate to the bottom of the front lip of the car out of the way of the radiator.

Remember to buy the rubber bushes for the radiator and remove the hood & intake pipes to make it a much easier job. Finally sand down and rust proof your drivers side ground at the same time to save yourself time in future.

Nice one, ta - great tip on the bushes and the ground, makes sense to do whilst it's all out the way.

[bob-bobberson]

s p a c e m a n said:

I bought an alloy one from here about 10 years ago and it's still perfect now.

https://www.aaronradiator.co.uk/vintage-car-radiat...

Ha - ironically that's where I'm going to get it repaired as it's close! Good to know they also do a new one if needed

[bob-bobberson]

TarquinMX5 said:

I don't know whether yours is a serp or pre-serp, but if the former it's worth checking (or replacing) the S-shaped connecting pipe that comes from the rad outlet up and over the chassis. If it's still the original steel one they can corrode; stainless replacements are much better.

I can't recall the hose layout of the pre-serp but it might have something similar. [If not sure, Serp has the ribbed single drive belt]

It is a serp, and that pipe has had it so I will be getting the new shiny one when I order the pipes.

[bob-bobberson]

An update on this:

Got the rad fixed at Aaron Radiators last week, not the cheapest repair in the world however the job looks good and the guys there think the original + new core is better for the long term than a new aluminum one.

They also showed me where the damage occurred - in my first picture, along the top (which is actually the left hand side, bottom of the radiator when looking from the drivers seat) is where the core has been worn by the fan shroud rubbing on it. I haven't had a chance to look yet, but when re-fitting I will be putting something between the fan and rad to prevent this happening again

Bit of a PSA for anyone else - check that this isnt happening to you too!

I have a new set of pipes from ACT (very nice) and a new stat - all I need is time to fit it all now and it'll be back on the road

[bob-bobberson]

Riff Raff said:

I'm not sure how any bit of the fan or the shroud could contact the radiator core on mine.

The shroud is effectively a "c" shape bolted onto the top and bottom of the radiator surround, and the fans are bolted on to the outside face of the shroud. The whole assembly (radiator, fans, shrouds) is solid once bolted up, and the individual bits can't move relative to each other, although the whole assembly can move relative to the rest of the car because the radiator is mounted on rubber bungs top and bottom on each side. See the photo below. OK, my car has an alloy rad, and the shrouds are alloy too, but the setup mirrors the original steel radiator and the original (horrid) glassfibre cowls.

I'd have to guess that yours had something loose somewhere.

Fair enough - maybe not on yours, but something has rubbed on mine, in several places on the core which has caused it to leak. I haven't had a chance to check the shroud yet, but there is nothing else it could be.

Still worth checking.

[bob-bobberson]

So, I've got it all fitted and back in. Aaron rads did a great job with the radiator, albeit for a hefty price! I put some rubber edging on the cowls which should hopefully stop any rubbing Pipes are nice and went in well.

Filled and bled the system today with g48 coolant, and have only managed to get around 5 litres in so far - is this normal?

Car gets hot and the fans kick in, the blower also comes out warm (but not boiling hot) - but the temp gauge shows under 50deg - could I have knackered the sensor when doing the work? I know there are threads on here to move the sensor etc, but it hasn't been a problem so far.

Just wary to trust it all when the temp gauge isn't rising

S

[bob-bobberson]

Just checked the gauge by shorting it, all worked so can't be a gauge problem. I'll clean and reconnect to see if that's helps

[bob-bobberson]

Belle427 said:

Probably an air lock they can be tricky to bleed

Yeah I keep bleeding it and there is small bits of air coming out so you're probably right. Just very jarring not to have any temp readings at all!

[bob-bobberson]

Classic Chim said:

5 litres is not enough by 1/2 literally.
Look up the specs for coolant quantity in a Chim.
It’s around 11 litres. 1/3 mix anti freeze but I put around 40% in so around 4 litres of anti freeze.

Yeah it did dawn on me yesterday that there must've been old coolant left in the heater matrix which didn't come out when I drained it a week ago. I'll make a note to drain it properly when I have time as it would be good to get it all out.

That being said, I fitted a new temp sender in the standard Range Rover slot as per this thread and it has made the world of difference. Took it out for a spin with the roof off and the gauge is more reactive, the car seems alot happier. Fans kicked in and went off at the right time, and the coolant level is full with no air coming out of the radiator.
Will monitor, but it should be good