3-litre radiator

[djm16]

How many cores do these have from factory?

The reason I ask is that I need a recored radiator, persisting overheating and leaking following rodding.

Mine has only two rows of tubes. It looks as though the tanks have been treated unkindly to get them to fit the core, the corners are bent in, and the brass split and crossed over. So I am not convinced this is an original setup or the the tanks are re-usable.

In comparison, my P4 has three rows of tubes and enigmas P5B has four.

[Phil Nottingham]

Just looked at mine but having not long got home the engine was hot and its difficult to see. The rad looks original and in good condition but I just cannot see how many rows it has for sure but it looks like 2.  I will look again at weekend

[enigmas]

Djm16, the radiator in my car is a custom made alloy unit...4 core as you noted, but obviously not factory standard (to cope with the extremes of weather in OZ).

You may find that your P5 3 litre 'original' core is not copper at all (and designed to retain heat rather than lose it (for the UK climate.)

Also be aware that the 3 litre radiator is rigidly mounted to the car unlike the P5B unit.

Note that changing the radiator core to a modern copper or alloy unit can incur flexing and constant weeping after a relatively short period... So consider mounting it with flexible (rubber) mounts. (How do I know this?)

[djm16]

Thanks for the replies. The comment about the 4-core rad was made TIC as I was aware this was a custom rad for a special car.
My local friend and advisor on all things Rover / mechanical tells me that in his experience maintaining these cars that the 3-litre should not be overheating in WAs 40 degree heat even on an original radiator, otherwise I would be looking at a customs N+1 row jobbie.

[enigmas]

The original radiator for a 3 litre may be fine with the extremes of climate in OZ..I really wouldn't know. At the time when I was modifying my MK3 P5 to take the P76 engine, the radiator specialist upgrading the core to a 3 core copper unit (initially) told me that the OEM radiator that came out of the car wasn't copper.

[djm16]

I was asking around our club for anyone with a radiator with tanks suitable for re-coring. I was pointed to an ex-club member living not a million miles away from me with a vast shed larger than the average 3-bed semi and garden, packed to rafters with P5 spares and many restorable and not so restorable cars. When I told him what I needed, he jokingly asked "how many do you need?".

To my surprise I came away with what looks like a perfectly usable rescued part. Not only that but is has THREE rows of tubes.

Not that it matters of course, but do we know if 3 litres were supplied with a 3-ply core for Australia spec cars?

Here are some pics of what mine looked like on dismantling. As I say above, a little disappointing that even after clearing out it still could not keep the engine temp down (although it was better).

[Phil Nottingham]

Mine has 2 rows and modern thin film fins although its at least 25 years old - it has the SERCK rebuild logo on it who were OEM

[Warwick]

Once you've finished all the flushing and you're ready to connect up the radiator, cut the foot off a pair of pantyhose and push it inside the top radiator inlet, then fold the "cuff" back over the inlet tube. Refit the top hose. Be prepared to have a little bit of coolant leakage past the hose clip as it will tend to seep through the pantyhose. Remove it again after several weeks of use and you'll be surprised by what you catch in it. Keep checking it until it no longer collects any crud.

When the final coolant fill is done, discard the pantyhose. This isn't a permanent filtration solution as it stops the radiator hose from sealing properly on the radiator inlet, and it probably isn't very durable, long-term.

[djm16]

I like the idea of filtering the coolant. I have therefore made a sleeve out of brass mesh to fit in the thermostat housing. It is easily removable for cleaning. Woe betide anyone who adds StopLeak or similar though!

Unfortunately the nice looking 3-core radiator is a bust. The core leaks in two places and the tank leaks from where it has been dropped on the drain tap. So still looking at re-coring something. JRW has advised that he can arrange a 3-row re-core, so maybe I have to fix up the old radiator while I wait till August to bring the one for recoring over from Australia.

[enigmas]

That's a long way to go for a radiator core?

[Warwick]

Feb 6, 2016 23:33:26 GMT djm16 said:

I like the idea of filtering the coolant. I have therefore made a sleeve out of brass mesh to fit in the thermostat housing. It is easily removable for cleaning. Woe betide anyone who adds StopLeak or similar though! ...

Make sure that the system is thoroughly clean first otherwise your strainer may become blocked. I've also edited my previous post to make it clear that the piece of nylon stocking in the top tank is only a temporary filter.

[djm16]

More information from the re-coring specialist.

I decided to bite the bullet and get this done in Australia despite my previous negative experiences with rad repairs and despite the higher price.

Apparently radiators now come in core thicknesses rather than number of rows. Mine is going to be re-cored with 45mm replacment. The radiator coming off was only 30 mm thick. The heat transfer tubes are now available in sizes other than 5/8".

Only slightly off topic, I tested my JRW re-cored P4 radiator today by driving it hard up Redhill (3km of steady 1:20) in 42 degrees. The temp gauge went up to 85 degrees (thermostat 77 degrees) but cooled down very quickly on the level.

[Warwick]

It's amazing how much difference core thickness makes. Years ago I replaced the belt-driven fan on the Range Rover with a pair of large electric fans behind the radiator, after the original plastic fan threw a blade while halfway through a tunnel. (Burnley Tunnel in Melbourne). Frightened the hell out of me. Lots of vibration and nowhere to stop.

I decided to also make use of the pair of small air-con fans in front of the radiator, so I fitted 2 capillary type thermostats and rigged up one to control the air-con fans and one for the new radiator fans. The air-con fans cut in several degrees before the main fans. It worked very well.

Then a few years later, the radiator needed repairing (again) and it was getting a bit tired. We're lucky to have a very good local radiator repair shop. Their opinion was it was going to be hard to do a good job this time. So I started looking on-line for an NOS radiator. A long-shot but worth a try. I found one on eBay in the US and I got it cheap. It cost me about A$160 (from memory) including air freight and it was delivered 4 days later. It looked a bit different. It was for a US model. After fitting it I realized that it was considerably thicker and my twin fans would no longer fit behind it without much work. I needed the car back on the road the next day so I decided to rely solely on the small air-con fans until I had time to solve the problem. It wasn't summer so it wasn't critical.

Anyway, it worked so well that I left things as they were, right through the following summer. That was several years ago now and the car has been in stop start traffic on 42 deg.C days and it doesn't overheat.

[djm16]

would the radiator you bought on eBay be for a P5b?

[Warwick]

No, it was for a US Range Rover of the same vintage. It dropped straight in, but where the original one had the same depth for the surrounding frame, this one's frame was 'full' of core whereas the other's core was thinner.