Ranger Mods

I'm having some issues with the engine temperature rising under load, especially when towing. Definitely not losing coolant, so suspecting thermostat and/or the viscous fan clutch.

The fan does have resistance when turning by hand, but doesn't seem to be much difference between cold and hot. So, does anyone here know for sure how 'tight' the fan locks up when hot? Does it lock solid or can you still turn it by hand?

A fan assembly is upwards of $300 so doing a bit of research before I decide what to do.

Cheers

When I was towing with mine I always had to manage temps, tried a dayco clutch and made no difference.

It will not solid lock. A bit of and indication test is to run it in park at say 2000rpm and watch your temp data. Probably drive it a get it hot first.

If the clutch is working the fan will start to roar as the temp gets up.

Thanks Bala,
I read a post somewhere with a guy having very similar symptoms and all he did was change the thermostat which he said fixed it.
I might try that first. I can test the old one on the stove to see if it's dodgey I guess.
I just want to make sure it's all good before towing the van again.
Cheers

With coolant refill if your egr cooler is still in.

I was looking at an aftermarket cooler and their info stated cooling system must be vacuum filled to ensure no airlocks.

I was also informed that following the ford manual is good.

I have a vacuum kit coming as I want to do a coolant change in both my fords soon and my landcruier is a pain to get all the air from.

While the coolant is out I would also look at pulling the radiator so you can clean the bugs etc from the fins of it, the intercooler and ac condenser.

I have done them while they are all in but hard to do a good job.

i fitted a mishimoto radiator, spelt wrong and a 180f or 82c trident thermostat

Just curious Jerry
What temp was on the stock thermostat?

Good question Ross, pretty sure it was around 87 (or 89?) but I know it was below 90. Mine now cycles around the 90 degrees and hasn't gone above 93 when pushing hard uphill with the van in tow. On a normal highway run it's around 87 - 88.

From bitter experience with silicon filled fan clutches on my past Land Rovers I have found that there are only two ways of testing them.
The first method is when the engine is idling and it must be up to temperature, this is important as the bi-metalic coil spring has to be heated by air flowing through the radiator to operate the valves inside the clutch and allow the liquid silicon to flow from chamber to chamber.
Use a rolled up newspaper and push it against the spinning fan blades, if there is considerable resistance then the clutch is okay and working properly, the other way - although far less reliable - is that when the engine is cold, try to spin the fan, if it spins freely the clutch is cactus, if it only turns 1-2 rotations its possibly okay and you should revert to the first test method.

GerryP wrote: ↑Sun Jun 04, 2023 8:17 pm Good question Ross, pretty sure it was around 87 (or 89?) but I know it was below 90. Mine now cycles around the 90 degrees and hasn't gone above 93 when pushing hard uphill with the van in tow. On a normal highway run it's around 87 - 88.

The OE Ford thermostat begins to open at 88*C and, if it's working correctly is fully open at 102*C conversely the thermostat by-pass valve is fully open at 88*C and closed at 102*C. The range being 14 degrees.

Normal engine temperatures are therefore in the range of 88 - 95*C ( 88 + 7 = 95 ) but on occassions such as very hot ambients and with full loads driving up hills towing etc you can expect to experience coolant temperatures up to and just over 102*C. The 50/50 OAT coolant and demineralised water you have in your coollant system has a boiling temperature of 135*C at 21 psi.

There is a small 10mm hose from the top of the thermostat housing / return coolant manifold to the top of the coolant reservouir, this orifice and hose allows air to bleed from the cylinder head to the tank, the orifice is only 1.5mm in dia and as I found, if it becomes blocked can cause the cylinder head to become air locked and a blown head gasket may well be the result.

GerryP wrote: ↑Thu Mar 23, 2023 10:34 pm I'm having some issues with the engine temperature rising under load, especially when towing. Definitely not losing coolant, so suspecting thermostat and/or the viscous fan clutch.

The fan does have resistance when turning by hand, but doesn't seem to be much difference between cold and hot. So, does anyone here know for sure how 'tight' the fan locks up when hot? Does it lock solid or can you still turn it by hand?

A fan assembly is upwards of $300 so doing a bit of research before I decide what to do.

Cheers

There are two ways of testing the viscous fan clutch.
If you can spin it freely by hand then its kaput, it sould cease to spin after 1-2 turns at the very, very most.
The other way is to allow the engine to get up to its normal working temperature, this will in 90% of cases involve taking it for a drive, then with a rolled up newspaper try to stop the fan from spinning, if there is zero resistance, the viscus silicon filled clutch is kaput, if there is resistance then its okay.

Suspecting that mine was on its way out I recently obtained a new one on eBay only to find that the original was okay so if you're desperate drop me as I'm not in need of a spare, if you're local to me I also have the tool to restrain the pulley and a 36mm open ended spanner to unscrew the clutch hub, with these its a 30 minute job to swap them, - without them it can be blood sweat and tears.