Technical Radiator advice, please!

Currently reading:
Technical Radiator advice, please!

RDS

Member
Joined
Apr 12, 2017
Messages
310
Points
131
hello all

My rad is blocked and leading to swift overheating problems. Checking the temperature of the rad surface as the fan cuts in, it is quite hot towards the top and cold at the bottom so i diagnose that it is blocked with sediment, unless anyone knows otherwise.

Therefore, please can i have your thoughts on the following from different suppliers:
"recore with brass and copper as is now" fairly local
"recore with brass and copper, two row X tubes, there's no space for anything deeper"
"send to us and we'll see what we can do (!)"
"Chinese new TIG welded aluminium rad with airbleed, 2 row 40mm core"
all at not inconsiderable prices that work out roughly the same.

Of course, I cannot find any OEM NOS stock

Recommendations and comments on the above, or other suggestions (apart from "Scrap it") please.

Thanks for your help.

RDS
 
Presumably you have checked for obvious problems in the rest of the cooling system e.g. Thermostat and water pump. Next thing I would do is take out the radiator and see what it looks like. Hopefully just sediment as you say and not a more serious problem with the metal tubes running from the engine which could spell big trouble. If all looks reasonably sound and rust free after flushing, I would probably go for the local recoring option. I have heard of X1/9 owners fitting a VW Polo radiator as a replacement but have no personal experience of this. Good luck!
 
Hello and thanks

I replaced the thermostat and given that there is a fair bit of heat at the top and upper sides of the rad i believe it to be blocked lower down. I've not had any luck with clearing out blocked rads before (or should i say that neither i nor the rad shop had any luck!). i did run RadFlush through with no benefit (worse if anything or maybe it has collected the sediment from elsewhere?)

Pipes warm to touch and slight weep of coolant even now cold at the hoses. They might as well go too and i'll fit the lower cut in/out thermo switch.

I am loath to take the water pump out for fear of a host of other issues: eg cracking mount or shearing a bolt.

Anyone fitted twin fans and can offer advice please?

ta v much

RDS
 
Fitting second fan is easy - the rad has studs on the other side to take another fan. Then all you need to do run wires to the new fan. You might be able to connect in parallel, but need to check fuse/relay. I was given good advice years ago regarding electrics - best to add complete new wiring rather add to whats already there. You might want to fit the second fan on a manual switch? I have a single fan, but have an override switch too!
I think it's preferable to solve the cooling issue rather than adding a second fan. When I get round to doing mine, i'll take it to local specialist to get it done.
 
A second fan isn’t going to help any if only the top half of the rad is getting hot. Coincidentally I’ve just sorted out a 1300 with the exact same problem, only the top third of the rad got hot and the temp. rose quickly after 5~10 miles.

I’d drop the rad out and check it’s overall condition and flush it out. On the 1300 it took me about half an hour of reverse and forward flushing to remove all the sludge and hard deposits, this sort of stuff came out:

Bah, can’t post an image link until I have 5 posts!

I also mixed up about 500ml of caustic soda and sloshed that around the rad for 5 mins, amazing how much extra sludge it removed. Be careful with caustic soda it’s nasty stuff.

Worth flushing out the transfer pipes at the same time, remove the engine side coolant hoses and flush through.

Afterwards the car ran fine, all of the rad got hot and the temp never got above midway on the gauge.

Also be carful with the bleeding, I found getting the rad below the expansion tank (car nose down) best when filling the system. Fill until coolant flows out of the rad bleed nipple, tighten and then run up to temperature. HTH.
 
Many thanks Steve and Neg

Yes, the extra fan won't help a clogged rad but i want to fit the extra fan after renewal.

I've taken the view that if the rad is that clogged (just as it was on another classic i had, with the same eventual results) dissolving as much as i can will only at best get me part way back to where the car needs to be with the cooling system and having drained, bled, changed the thermostat and done the whole thing two more times plus the flushing process involving yet more flushes etc, I think a new rad/recore is the way to go. When i did this on the other car, i ended up having to recore are the sediment had set solid and no amount of acid/alkali would shift it and it just added the time on. Having said that if i get a new rad instead of a recore then i will use the acid/alkali and keep the rad as a spare!!

Interesting you use the nose down technique Neg, I would have though leaving the bleed at the rad open would have had the same effect?

The pipes under the car, i will clean out and replace hoses and use the lower temp cut in/out switch. Did you use the wire clips or new jubilee clips for a good seal?

I saw that the rad has the extra mounts already factory supplied by FIAT for the second fan (presumably for hotter climates?)

If anyone has a wiring diagram or set up advice for the extra fan please advise: what fan motor was used?

cheers

RDS
 
Last edited:
I also have proof the nose down method works best, having tried this the first time I drained the coolant compared to level ground the next. Would always use new jubilee clips for the small extra cost involved.
 
Many thanks Iggy

re the clips, it was not the cost so much as the effectiveness of the spring-type ones supplied by Fiat as against the standard jubilees, that i was wondering about!

RDS
 
If you left the rad bleed open when running the car you would loose the coolant. With the nose down the rad fills to the top. You can always open the bleed later after the car has cooled down to let any air out.

I used new jubilee clips, never liked those wire ones...
 
I filled with the bleed open, until the coolant wept out of the bleed on the rad, then closed, continued the fill then ran it and bled again later, just as i do on the house central heating system. I would have thought nose up would assist here rather than nose down!

I favour jubilee clips too and in the Haynes manual i now see that Mr Haynes is disparaging about the FIAT clips used on the cooling system!

cheers

RDS
 
You need some pressure behind the air to expel it, I’d rather not open the bleed nipple when the car is hot nose up. With the nose down and the wight of the coolant behind it any trapped air in the rad will be pushed out.
 
Interesting. When I filled on the level and cold, the coolant reached the top of the rad and the open airbleed very easily. The bleed can then be turned off. No trapped air judging by the temp at the top of the rad when running later, just very cool at the bottom due to silting up. I keep an eye on coolant levels frequently too; over a short time trapped bubbles of air should surface.
 
The VW radiator mentioned in one of the replies is from a VW scirocco. They are cheap and work well. A little bigger than stock and need some modifications to make it fit, including adding a new bleed valve. The big win is they are readily available and cheap(found one on ebay for £30).

Money no object I would be tempted to try the Chinese Ally rad, but a recore will work pretty much as well. While you might be able to clean out the old one, odds are that the fins are past their best.

If you have the water going to the auto choke, I found this the best way to bleed the cooling system. My technique was to remove the top pipe from the auto choke, add a temp hose and fit a short pipe to the other. Put both in an open bottle (I had a glass jar I could stand on the engine/inlet manifold) with some coolant. Run the engine with it like this, raise the rear of the car if you can (nose down) and you can watch the air bubble out. Keep the coolant level 2/3 full and when it stop bubbling its done. refit the hose to the auto choke.

Hope this helps
 
many thanks for this also Alex.
I looked at the mods required for the scirocco rad and given they weren't as cheap as you found, I concluded that the ally rad was the way to go. Unfortunately the dimensions are slightly off, ie 15mm taller and so a b#gger to fit anyway!

Yes I bleed and part drain from the autochoke feed.

I'll report back further.

Cheers

RDS
 
Good luck with the install, a new ally radiator will be perfect. If it's a little bigger try and find a way to extend the bolts at the bottom.

Is the one you are look at the same as the ones from ebay?

The siroco rad, I just had a search on ebay and they all seem to be from germany, but very cheap.
https://www.ebay.co.uk/itm/KUHLER-WASSERKUHLER-VW-GOLF-2-83-92-JETTA-2-84-91-1-6-1-8-SCIROCCO-53B-1-8/390915686404?hash=item5b04640004:g:3scAAOSwGPxZ~yaO:rk:5:pf:0

Might be too late but could help someone else perhaps.
 
This post contains affiliate links which may earn a commission at no additional cost to you.
yes same ones.

scirocco good find but like i said the extra faff put me off!! Others will be nore adventurous...

cheers

RDS
 
Hi I replaced my X/9 radiator with an alloy one from Alfa 33, slightly smaller in surface area but is deeper, Dropped engine temp by 15 degrees, and never over heats thru mountain roads. Can be found cheap on eBay. Had to modifiy bottom mount and add top bleed hose,
 
Hello, I have fitted dual fans at one point.. It is true the second fan needs a secondary relay triggered off the temp switch and a second power wire installed from the battery. It works ok but what I found was these stock motors on the fan draw a termendous amount of current which draws and loads the alternator quite a bit then resulting loss of power. What I ultimately done was aquired a Marelli motor out of a Lancia fan which I had installed on the stk X19 fan support brackets.. The Marelli fan (used also in vintage Ferrari and Lambo's) is very efficient and quiet. Another thing to check as well is the water pump flow. Pumps are known to get weak in pressure overtime and will flow well with higher RPM but flow not so well when idling.. there is over 11 liters of coolant to push around in the X19. I hope this may shed some insite on your dual fan question.
 
Hello Breeze2

many thanks for the input there. I have installed the second fan and motor (am glad i did that before installing the new radiator) but have not connected anything to it yet.

Yes, I was worried about the feed wires also. I was thinking to uprate the relay and the wires from there to the junction where the two fan feeds separate.

The draw on the alternator is worrying: measured when running at 12-15A each with an initial much higher cut in spike (measured at 75A!). I say this is worrying because when the single fan cut in the other day i immediately had rough running. This happened twice in succession. However those more experienced than me say that it was merely a coincidence.

cheers

RDS
 
Back
Top