Odd overheating situation...

[Rafael]

I've got the oddest overheating situation going on with my '89 2.9l Ranger.

For years I would never get heat in the cab until the truck ran for about twenty minutes. I replaced the heater core. No change. The radiator started to leak so I replaced that, and the hoses at the same time. Then one day in the middle of summer the heater starts putting out profuse heat. As soon as the weather changed to cold NO MORE HEAT. And the truck starts overheating and stalling when hot at lights, sometimes even cutting out while cruising.

SO, I replace the water pump, but the old one was fine. OK, can't hurt to have a new pump. But still it acts strange. So I've replaced the water pump, all the hoses, the radiator, t-stat and the heater core, and no heat. The circulation seems week. THe heater hoses get warm but not really hot. I looked to see if there was a valve like on the 3.0l [vacuum assisted] that cuts off flow but nothing I see on the 2.9 like that....everything looks pretty straightforward on the engine.

Oh yeah, no white smoke or H2O in the oil.

Any ideas?

 

[shane96ranger]

What thermostat temp did you put in? Is the fan clutch working properly?

 

[Rafael]

I forgot to mention, brand new fan/clutch [the old one froze up and unscrewed itself!] as for the t-stat, I've run both a 195 and a 180, no difference.

 

[Harris]

Sorry to play Capt. Obvious, but do you have good tension between the belt and the water pump pulley?

 

[Rafael]

Sorry to play Capt. Obvious, but do you have good tension between the belt and the water pump pulley?

Yep.

 

[Harris]

So the water pump is turning, yet the circulation seems weak...
[Just kind of talking through it...]
You could have crud in the block or somewhere along the way making a blockage.
The thermostat isn't opening all the way up making a blockage. (But you did say you have tried two of those and had the same issue...)
There isn't enough coolant.
I mean, based on what you said originally there aren't a whole lot of things it could be.

Let me ask....have you tried it without the thermostat in it?

 

[Rafael]

So the water pump is turning, yet the circulation seems weak...
[Just kind of talking through it...]
You could have crud in the block or somewhere along the way making a blockage.
The thermostat isn't opening all the way up making a blockage. (But you did say you have tried two of those and had the same issue...)
There isn't enough coolant.
I mean, based on what you said originally there aren't a whole lot of things it could be.

Let me ask....have you tried it without the thermostat in it?

I have tried without a t-stat, same. And when I replaced the water pump the block was pristine, with nothing visible in the water passages, though I know that doesn't mean nothing else like that is going on, it just didn't have the look of a clogged block etc.....

The weirdest thing is how it will blow too much heat during the summer months [70s-80s] but when it cools off, no more heat. During the summer I can keep it under control by running the heat full blast, of course driving is miserable that way...sitting at a long light when it's 85 out with the heat on full blast is NOT a way to remain comfortable!

 

[shane96ranger]

What is your temp gauge doing?

Sent from a Commodore 64 using a 300 baud modem

 

[Rafael]

What is your temp gauge doing?

Sent from a Commodore 64 using a 300 baud modem

In the 12 years I've owned the truck the temp gauge has never worked. I've replaced the sender about ten years ago but it didnt' help.

 

[sjr53]

Get a new 13 lb radiator cap and use only a 195 degree thermostat. I block my radiator with cardboard that has a 6 to 8 inch hole in the middle once we get 10 degree weather or colder.

 

[martin]

How could the fan clutch unscrew itself. If it's running in the right direction the drag on the fan should keep it screwed to the pump. I'm not very familiar with the 2.9 but if there is a v-belt version and a serpentine belt version it's possible there might be a standard rotation pump and a reverse rotation version. I've seen this happen with 4 liter jeeps.

 

[Explorin94]

I forgot to mention, brand new fan/clutch [the old one froze up and unscrewed itself!] as for the t-stat, I've run both a 195 and a 180, no difference.

Wait a mnute here.......the fan clutch "unscrewed" itself from the water pump? Like simply fell off with no help from you and didn't destroy anything? The fan clutch is treaded so it actually tightens up when the water pump is turning. If it unscrewed itself as you say then something is severly wrong with the routing of your serpentine belt. Either you are describing it wrong or you need to check the routing of that belt because that fan clutch should never have come loose.

Sorry Martin I read his post and diidn't see yours.

 

[freedom5]

Weird - I agree the fan clutch should never unscrew itself even if it locks up. I replaced my thermostat with one that fails "open" if it goes out. They only cost a couple of $$ more and can be a life saver if the stat does fail - better to run cool than overheat.

 

[shane96ranger]

Yeah... that's an odd deal for sure. It's been a really long time since I worked on a 2.9, but I really see no.way of messing up the belt configuration. As I recall, it's only one belt unless you have A/C. And that would be really difficult to mess up.

But yeah, if you've somehow got a reverse rotation pump (if there even is such a thing) I think we know what your weak pressure and strange heating characteristics are coming from.



Sent from a Commodore 64 using a 300 baud modem

 

[RonD]

Yes, incorrectly routed belt would account for all the symptoms, water pump spinning in reverse direction, but I think the 1989 2.9 used separate V-belts, which are hard to mis-route.

Yes, 192-195deg T-stat is what you need to get engine to correct temp ASAP