Time to replace the radiator?

[Richyd]

Hey guys, first hot day yesterday (28) and Pajero started overheating when towing a trailer with AC on. So, thought I would do the thermostat and coolant today. I don't know the history of the car and am worried there may be some gelling going on (read about it many times). So I'm think of replacing the radiator soon and just want peoples experience in the area.

Lots of info on the forum here...lots of people saying to go somewhere like natrad and have it replaced (or buying one through them at least), a few posts on here about people who have bought them off eBay and seem happy.

It still looks like the stock radiator, so I thought replacing it may be the way to go (other option is having it rodded but given its age, ithought a new one may be a better option).

What are peoples thoughts- is it worth getting it rodded or replacing it?

If replacing, what are peoples experiences with eBay ones? Some of them look quite good- I'm read about upgrading to the thicker radiator as well, so I'm thinking that may be a good option??

[spot01]

The other possible issue to read up on is the fan clutch, as these have caused quite a few people to have issues. They can be quite tricky to diagnose. You should be able to hear the fan roaring if it is working properly when you accelerate in hot conditions.

[Richyd]

I can see the fan going....I can't hear anything unusual...
Anything in particular that I should look for?

[Scooby]

The local radiator repairers that I use, said they would not refit a plastic tank if it had age on it and give warranty. The tanks become brittle and will crack.
They also said that replacement plastic tanks are getting harder to source at a reasonable price to make it cost effective.
This was not just Pajero related but in general.

[Richyd]

Hey scooby, yeah I had heard the same.
That's why I am leaning towards getting a new one...but not sure at this stage.
Fan may be an issue, so I'll have to look into that, but I figured a new radiator (maybe one of the thicker core versions) may be a good idea anyway!

[spot01]

I can see the fan going....I can't hear anything unusual...
Anything in particular that I should look for?

The viscous clutch can lose it's strength when old - the fan still turns but the clutch isn't strong enough to pull enough air through when needed. This has tricked many people into thinking it is OK when it isn't. It should roar loudly when driving in hot conditions, like when pulling away from the lights - you should hear it clearly as the revs rise through each gear. If you can't hear it, that may be the issue.

There are plenty of threads on this topic - worth reading.

[Scooby]

Two trains of thought on radiators.
Single cores like Pajero standard, more air flow equals better cooling.
Twin core more coolant flowing slower but with a slight reduction in air flow and slight increase in air temperature are rear cores equals better cooling.
One thing the radiator repairers told me was that the NM didn’t need a bigger radiator, it just needed everything to be right, clean radiator, good thermostat, water pump and fan clutch.
My NM has a problem overheating in stop go traffic, it has a eBay alloy radiator I think 50mm, I have change re oiled the fan clutch and put a new one in changed thermostats, still overheats. If I put it in park or neutral and bring the revs up to 1000 1500 rpm it cools down easy.
Was thinking I may have water pump issues.

[Richyd]

Thanks spot. I had a read through some other threads and we you replied the first time. I'll do the coolant change etc, then when the engine is hot I'll have a go at spinning it and see how it goes!

[Kingmarz]

Find the issue before possibly wasting money on eBay alloy a one which are no better than the factory plastic end ones.
First check the fan
Second get out there with the garden hose and flush the system remove heater hoses, top radiator hose and thermostat housing and just flush all ends multiple times.
Then get a torch or phone and see if you can see light through radiator and condenser hose is with a bit of pressure and clean it.
Some will run just water or flush product for week and reflush.
I did this procedure to my Pajero not long after purchase and my concrete driveway was totally covered.
Or you could just buy a eBay alloy upgrade but just don’t expect it to be any better in quality than the factory plastic ends one.

[erad]

Richyd:
Most of the cooling issues involve the fan clutch. One way to test it is to have the engine hot and running, and then shut the engine down. The fan should stop almost immediately. If it runs on for a second or two, the clutch is stuffed. You should feel some resistance when trying to turn the fan by hand (engine stationary of course). The ultimate way to test the clutch is to try to stop the fan whilst the engine is running. I do this by getting a piece of wood and CAREFULLY push it into the blades on the trailing edge (so that the wood acts like the pawl on a ratchet). This would be on the underside of the fan from the left hand side of the car. Do not try the upper side because the wood may get caught and then flung out, injuring you or damaging something. If the fan clutch s stuffed, you will be able to stop the fan from spinning. On my old Range rover, I was able to actually stop the fan with my hand, but I do not recommend trying that as a test until you are completely sure that you will not be injured.

You may still have the internals of the radiator cagged up with gunk, but at least check the fan clutch before you do anything else.

[disco stu]

Just to comment on eBay radiators. I'm likely one of the people who sang their praises. I've been running cheapies in both Camry and falcon for about 6yrs (from memory) and both have been fine up until now. I've just noticed the Camry one is starting to leak where the tanks are sealed to the core, just weaping out a bit of coolant. I was happy with my purchase for the price-it cooled great and caused no issues, so I've just ordered another eBay cheapie.

I guess it depends on what the cost is for a more expensive version. The falcon one is still going fine, touch wood. They were both purchased within days of each other

[HomerJ]

Beware of buying a cheap replacement radiator on ebay. I should've learnt my lesson by now but I bought one for $250 a few months ago and it didn't fit, despite the seller insisting it would. One of the tabs was 25mm out and it was returned. I ended up spending $500 but I had it the next day and I knew it was going to fit.

[Richyd]

Well, flushed it out as best as possible with a hose, replaced the thermostat and coolant- still overheating!

Erad- I didn't see your post about the clutch tests before. Wish I had because the engine is cool now.
I tried turning the fan when hot and it still seemed to have resistance (maybe turned 90 degrees off a decent push around before stopping). I'll try the piece of wood tomorrow and see.

I think it may be the radiator as feeling across the fins, there are some areas that are hot to touch, whilst other areas are quite cool. To me this makes sense as gunk would stop the hot water flowing through (so fins that are blocked would be cooler). I'm definitely still testing the fan before going further though!

Cheers everyone for the help!

[nj swb]

I tried turning the fan when hot and it (maybe turned 90 degrees off a decent push around before stopping).

I'd class that as a fail.

I'll try the piece of wood tomorrow and see.

Good idea.

You may be right that the radiator also has a problem, but a dud cooling fan will give problems even with a good radiator.

Make sure the fan is good before you replace the radiator.

[Richyd]

Ooops, thanks NJ.
For some reason I thought that was good!
I thought if it was dodgy then you expected 1-1.5 full rotations before it stopped (360-540 degrees).

I'll try the wood trick and see tomorrow!