Blocked radiator?

[draenog]

Hi,

When I got my +2 a year ago it had red coloured coolant in it (presumably OAT). I always use the blue coloured (IAT) coolant in my MGB so I was somewhat surprised but it seemed to be running OK so I left it. However, after some recent coolant loss, I read the various threads on the issue and decided to completely flush the system and put IAT-based coolant in it.

So I've drained the system (pulled bottom hose off the block as the petcock was completely stuck). Flushed it with water, refilled with water, ran for 10 minutes at temperature, drained. Then refilled with water, added a radiator flush, ran for 10 minutes at temperature and drained again. At this point I hadn't taken much notice of how much water was need to fill the system as it came from a big container, but it didn't seem to take much to fill it. This was confirmed when I came to put coolant in, as I only managed to get approx 3.5 litres in before the radiator was full (including squeezing of hoses to get air out). This is less than half the capacity listed in the service manual!

So does this indicate the radiator is half-blocked? I used a chemical flush because there was a large amount of whitish sediment in the radiator (the first lot of coolant that came out also had a lot of sediment in it). The flush doesn't seem to have done anything much though. In the past, I've never had an issue with overheating, but I've not used it in busy traffic. The reason for the coolant loss mentioned above is that last weekend I ended up waiting in a queue of 6 cars at the petrol station - coolant and steam began shooting out the overflow bottle. At the time I decided I must have knocked the top off the bottle when refitting the air hose earlier but it could indicate I do have a cooling issue and I've been lucky.

Considering the flush didn't work, I expect this means I need a new radiator. Any suggestions where I can get a rebuilt narrow radiator (with otter switch) from? I imagine it's the original radiator as it has STANPART embossed on the top. I prefer to keep it original.

Thanks,
Rob.

[richardcox_lotus]

I think the capacity for my ?lan is 4 and a half litres, but that includes the heater matrix. When I tried to refill mine I couldn't get it that volume in.

So maybe 3 1/2 for a plus 2 which I believe has a different setup may be ok.

May be worth taking for a decent run and seeing if the level settles ?

[rgh0]

The bottom hose will not completely drain the block or heater so I suspect the volume is about right.

I would pull the radiator and flush it thoroughly to ensure it is clear. I would also remove the drain on the block and clear it if the hole is blocked up with some wire and flush the block through the drain to remove any loose sediment in the bottom of the block also and remove the heater hoses and flush the heater also.

Once everything is free of any loose sediment then refill give it another chemical clean, drain and flush it again and then refill with antifreeze.

Time consuming I know but once that's done you should be OK from an internal cleanliness perspective

cheers
Rohan

[draenog]

Hi Richard,

Thanks for the feedback. That's reassuring. Hopefully I'll be able to fit an extra litre in once it's circulated (have to wait until I get home from work, I ran out of time this morning).

Rob.

[draenog]

Just seen Rohan's reply. Stupid question, where is the block drain plug? Can you access it from above or below, and do you need any tool for it (guess just a socket)?

Thanks,
Rob.

[draenog]

Sorry to spam the forum, but I pulled the bottom hose off the block rather than the radiator, as I thought the kiink would prevent the block from draining...

[RichardHawkins]

Rob,

For my radiator I used a company called Cool Experts in Nottingham to re-core it. My car is still in bits so I don't know how it will work, but it looks like a good job.

My industrial experience of de-scalers is not good. If there is a passage that is scaled the de-scaler will flow through that passage and clean it, but if the passage is blocked, the de scaler can only attack the scale from the end of the blocked passage, so results
are very slow. Also because the de scaler solution is being pumped around the cooling system by the engine cooling pump, the solution will take the path of least resistance and flow preferentially through the part of the system/radiator that is cleanest. That's why I had my radiator recored.


If I remember correctly (I am away from home at the moment) the block drain plug is on the exhaust side towards the rear of the engine and is made of brass. In my case having removed the plug nothing came out, as the bottom of the block was full of a rust coloured sediment. I was doing an engine overhaul so I removed the core plugs and cleaned as much sediment as I could, pressure washed it, reassembled and used a de-scaler.

Richard Hawkins

[billwill]

When cleaning a radiator it is best to REVERSE flush it.

I.e make the water flow the opposite way from normal usage. This will help push any sediment out.

Use a garden hose on maximum flow. Wedge it in with a cloth wrapped around it as a seal.


{be prepared to get wet yourself }

[rgh0]

Yes The block drain is at the rear on the exhaust side. It may be just a plug or it may be a drain tap. In either case you need to remove it as the hole will probably be blocked with sediment. Its a real pain to get to as the exhaust is in the way.

When you remove the bottom hose from the engine you drain it through the water pump and this goes into the block about 1/3 of the way up so the bottom third of the block does not drain.

cheers
Rohan

[Plus 2]

Hi,

Just as another suggestion when cleaned out/flushed albeit a slight on cost always refill with softened pure/de-ionised mineral type water mix with the anti=freeze. The type generally used for batteries or domestic steam irons.

All our prototype and production cars were filled up this way and we had water softeners specifically fitted in the prototype workshops and production plants.

Here in France I can buy a 5 litre container for less than 2 euros.

Regards

Steve

[Hawksfield]

Draenog

When you get water in the system run it till the stat opens then you will be able to feel the surface of the radiator tubes, they run top to bottom, so feel across the radiator and check for any cold tubes. This how I discovered blocked tubes on my +2 I had it re-cored with triple row tubes no more probs.


Good luck

[draenog]

Thanks to everybody for the replies. Last night after work I removed the radiator from the car and flushed it with the garden hose (forwards and reverse, in several orientations). Looks much better now (I could see several of the tubes were blocked, these at least are now clear). Strangely, the exterior of the radiator looks pretty good, with only a couple of bent fins. The paint work is also pretty fresh, so it could already be reconditioned (doesn't look over 40 years old). But how it ended up so full of gunge (adding OAT to IAT?). As to the reason why I couldn't open the petcock. Now the radiator is out I can see it's been soldered shut

I'll try flushing the block next, but I won't have time to do this until the weekend. That's a good tip to feel the surface of the radiator tubes (Hawksfield). If any are still cold after flushing it may be easier to just get a new radiator.

Thanks,
Rob.

[draenog]

The cheapest place I've found locally to get antifreeze and de-ionised water is Wilkinsons. De-ionised water is 79p a litre and IAT antifreeze 3.99 (i.e. 2.39 for a litre of coolant, or there's ready mixed at 3 pounds a litre). The prices in the nearby garages are ridiculous.

Rob.

[Plus 2]

The cheapest place I've found locally to get antifreeze and de-ionised water is Wilkinsons. De-ionised water is 79p a litre and IAT antifreeze 3.99 (i.e. 2.39 for a litre of coolant, or there's ready mixed at 3 pounds a litre). The prices in the nearby garages are ridiculous.

Rob.

Amazing Rob.........I bought 10 off 5 litre containers of de-ionised water when on offer at our French Eleclerc superstore for a euro for the 5 litres each and threw the water down the drain.................I wanted the containers to fill with wine from our local vineyard as that was only around 79p a litre......... actually 1 euro (hic)

Regards

Steve