My cooling obsession isn't healthy and although much better....I still percieve a cooling issue with the rover.
Low range and off road its fine.
In high range:
hills even for a short burst causes the new gauge as well as the oem coolant gauge to rise. A long hill will cause it to get around 205°. Normal operating is just under 190° indicated.
Towing creates similar results. I have supplemental electric fans in the old a/c spot with a switch that turns on at 205°.
Cooling system is new through out. EVERY component in the circuit is new within the last year.
Now its an 87rrc. Lots of heavy metal stuff on it and 265/75 tires....so that doesn't help the old 3.5.
The electric water pump post gave me an idea....although I don't think and electric water pump drive is the answer for my rover.
The radiator seems to do its job. The outlet side of it seems very cool.

So what my thought is....what if the coolant just doesn't circulate fast enough? Could putting a slightly larger pulley on the pump be of help? It would move the pump faster as well as the fan.
Probably a foolish idea....anybody have any insight?

and yes...I'll concede that maybe the motor is just plain tired....and in need of a replacement...but those funds just aren't there quite yet.

you'd want a smaller water pump pulley to speed it up.

you'd want a smaller water pump pulley to speed it up.
That's an important detail.....whoops.

Instead of wasting a bunch of money trying to find a smaller water pump pulley (I don't even know if they exist), why not remove your t-stat? Obviously the truck will not warm up properly, but the bottle-neck at the t-stat will no longer be there and the coolant should flow faster.

Anyway, if you think coolant flow might be the answer, try this and see if it helps the temps during climbing or towing.

After watching you fight this problem what seems like forever now I have a clue for you. Remove some or all of your freeze plugs. I think your engine is full of rust and corrosion. It will be most evident at the back of the block. So remove the back two freeze plugs on either side of the engine. Take out the thermostat and flush the engine with a garden hose to clean the block in the vehicle. Do not be afraid to poke around inside the block to loosen debris. Problem solved two freeze plugs.

JP

hmm...I may give that a try.

I'm getting some light pinging on hard acceleration (only after the engine warms up -- it actually runs better when cold) and I just noticed some high temp readings when driving up grades on the highway (no problems with overheating in town) so I'm suspecting a clog in the cooling system somewhere. Thermostat and hoses are all only 6 mos. old and the radiator is 4 yrs. old.

I'm going to get the radiator rodded and opening the freezer plugs and hosing the water jacket out sounds like a good idea. Just a couple of questions from a rookie: where are the freezer plugs on a 4.6, what do they look like and how do I get them out?

One other question, is there an aftermarket, bolt-on radiator available for a '95 Disco that cools more efficiently than the stock unit?

Thanks,

Norm

OK, I found the freezer plugs (square bolt head below the exhaust manifolds) so I can take care of the coolant flush.

One more question: how do you know if the viscous fan coupler has failed?

I assume the fan is supposed to turn freely when cold and then lock up when hot. The way it is now, I can get the motor hot, shut it down and immediately check the fan and it still turns freely. Does that mean the viscous coupler is fried?

Thanks,

Norm

I assume the fan is supposed to turn freely when cold and then lock up when hot. The way it is now, I can get the motor hot, shut it down and immediately check the fan and it still turns freely. Does that mean the viscous coupler is fried?


Sure sounds like it. Even when cold there should still be some resistance.

Pete

Well, by "turning freely", I mean there is "some" resistance, but the fan can easily be turned by hand. There appears to be no difference in this resistance between a cold or a hot engine. When the hot engine is shut off, the fan continues spinning until it runs out of momentum.

So...I take it I need to start shopping for a new viscous fan coupler. Are there any bolt-on aftermarket viscous couplers that would perform as well or better than the OEM unit for less money?

Thanks,

Norm

Well, by "turning freely", I mean there is "some" resistance, but the fan can easily be turned by hand. There appears to be no difference in this resistance between a cold or a hot engine. When the hot engine is shut off, the fan continues spinning until it runs out of momentum.

So...I take it I need to start shopping for a new viscous fan coupler. Are there any bolt-on aftermarket viscous couplers that would perform as well or better than the OEM unit for less money?

Thanks,

Norm

The CB option is to put a bolt through it. Two bolts if you're worried about balance.

Well, I went ahead and got a new viscous coupler and installed today. Just wondering if there are any aftermarket fans to fit a '95 D1 (serpentine belt) that are as good or better than the stock unit for less $$.

Thanks,

Norm

The CB option is to put a bolt through it. Two bolts if you're worried about balance.

I would be more worried about fan blades disintegrating from the fan spinning at too higher RPMs, the other function of the VC unit in the fan is to stop the fan from running up over 4000 rpm and failing/fatiuging.

I have seen late '80s ford vc units that are a direct replacement.

There are threads on outerlimits by RUFF about this IIRC
and one or two here as well

Tom

derale makes a replacement fan that fits. pn 17917 , summit racing carries them for $31.99 its a special order item but it didn't take very long when i ordered mine.

derale makes a replacement fan that fits. pn 17917 , summit racing carries them for $31.99 its a special order item but it didn't take very long when i ordered mine.


Thanks for the info! That's less than half what the OEM part costs.

Also wondering if there are any bolt on aftermarket radiators for the D1 that are more efficient than the stock unit. What are the pros and cons of getting an aluminum radiator? If aluminum is the way to go, can get my old stock radiator recored with aluminum guts?

Thanks,

Norm

beware of removing the thermostat,this can reduce the pressure in the system and cause localised overheating at the rear of the engine.
we used to replace the stat with a disc with a hole in to get round this when racing V8s

What are the pros and cons of getting an aluminum radiator? If aluminum is the way to go, can get my old stock radiator recored with aluminum guts?


Aluminum disipates heat better then copper.

Aluminum is harder to repair. The tubes dont crimp and roll like a copper core. So you need to bring some JBweld along for trail repairs.

Seems to me, if you remove the thermostat, or add a smaller pulley to the water pump, you are speeding up the coolant. By speeding up the coolant, seems the radiator would not have a chance to cool the fluid....Seems, the longer the antifreeze stays in the radiator, the cooler is will get...To a point.

Seems to me, if you remove the thermostat, or add a smaller pulley to the water pump, you are speeding up the coolant. By speeding up the coolant, seems the radiator would not have a chance to cool the fluid....Seems, the longer the antifreeze stays in the radiator, the cooler is will get...To a point.

Yea, but the objective is not to minimize the temperature of the coolant leaving the radiator. The objective is to optimize the heat dissipation. This heat dissipation benefits from a hight temp difference between the radiator and ambient air, thus higher flow is better, even if it means slightly hotter coolant entering the engine.

Yea, but the objective is not to minimize the temperature of the coolant leaving the radiator. The objective is to optimize the heat dissipation. This heat dissipation benefits from a hight temp difference between the radiator and ambient air, thus higher flow is better, even if it means slightly hotter coolant entering the engine.

I don't think it will work...At least, not at idel speeds....Try some Water Wetter...

I don't think it will work...At least, not at idel speeds....Try some Water Wetter...

Do a search on sachilles and Watter Wetter.. he has done some extensive work on this.