I have a 87 2.9L 4x2 all original 97K mile on the engine. Very well maintained. I replaced the water pump last fall. Flushed the engine and back flushed the heater core. Radiator 6 years old. Noticed the engine gets to half gauge when in heavy city traffic in outside temps in the 80s. After picking up the speed to around 40mph gets back down towards what I call normal. Hwy speeds does ok. I'm thinking with 97K miles and engine around 30 years old. It is probably time to replace the fan clutch and fan. The fan blades have cracks at the fan hub on all the blades. The engine has no leaks and clean so no issues with oil and dirt to cause any heating issues. I would like to find a new clutch and fan online somewhere that does pay pal credit? Money a little tight and not so plenty. I've seen the threads on electric fans. Don't know that I need to go that route yet or a electric assist fan. If I have to are there any recommendations on an assist fan in front of the radiator?

 

RockAuto.com
But if money is tight, I'd look to see if your thermostat isn't stuck open, and if it opens at the right temperature first. That Temp gauge should be right in the middle while you're running. There is the proper coolant level in the system, right?
Next thing to look at is the ECT sensor, if your truck has one. If that's not working correctly, you could be burning through a LOT more gas than you need to be.
If that checks out, test your fan clutch. (search on here for the method)

Sure, an electric fan can lower the load on your engine and save you fuel. If you're looking at doing that, also check to see if there is an underdrive crank pulley for your engine - they go together in my opinion, and bring your engine to about the most efficient it can get coming from the factory, even after all these years. And if you have emissions testing in LA, using less gas lowers your emissions theoretically.

 

I had previously replaced the thermostat and temperature switch that goes to the gauge. The ETC sensor (2 wire Blk and white) I believe goes to the computer. I haven't seen any code flashes but there could be a minor alarm. Need to dig out my code/flash list and see if there are any.

Typically the gauge shows needle on "m" of Norm which is 1/4 gauge regardless of how it is driven. It is only in heavy stop and go traffic that it comes up to half gauge or a little more in 80 degrees outside temps that concerns me it being an older engine.

One thing I haven't done that has a tendency to get overlooked is checking the timing. Don't think that has ever been done on this truck. I've kept close documentation on this truck since new. Idling and low rpms may be something to look at since it is occurs when standing still. Don't know if I can do anything about the idling since it is fuel injection. If that plays out then I'll look at the fan and clutch. I believe I've seen 7 blade replacements on this year model instead of the 6 blade I have.

I don't know what the test is for a non electrical clutch. If I'm not mistaken the way mine works is there is a fluid or oil that is heat sensitive that affects the speed of the fan.

 

My bad on the gauge - I hadn't realized you're in an 87. The gauges were different back then. I'm going to venture a guess that your cooling system internals are just fine, but you're right to be looking at the clutch and fan itself.
(man, an 87 2.9 with less than 100k miles on it? You must live right next to the church you intended to drive it to on Sundays )

An assist fan would be overkill, IMO, unless you've done some tuning or whatever to generate more heat within the engine (which I would consider just beginning to get broken in). So maybe if the fan blades are cracked, they're wobbling/flapping and not drawing the right amount of air. And if there's a problem with the clutch, they generally seize so that they're always engaged and turning, OVERcooling the engine, denying it the opportunity to get up to proper operating temp, but that's likely not the case here.

At this point, it's totally up to you how to approach the repair, and it'll get down to money; either keep it bone stock and replace what the factory put there, or "upgrade" to an electric fan. The E-fan might cost you more initially (I'm sure Flex-o-lite can fix you up with a kit; you may need an alternator upgrade), but you'll get it back over the years at the gas pump with slightly improved efficiency.

Another thing to mention is that there are additives for the cooling system that may help you keep the engine at a lower, steadier temperature, like when under load getting on a freeway, climbing hills or in stop-and-go traffic, taking some load off the cooling system itself.

 

Its been a really sweet vehicle. I bought it in 2001 from the company I work for and it had 14K miles on it then. It was seldom driven mainly because it didn't have AC in it. I was quite familiar with it and the garage gave me the repair records on it. Maintained documentation since then. Got it for a song and dance. It's on its 3rd set of recently bought tires. Never given me a bit of trouble other than just aging parts. Never hauled anything. Bed isn't even hardly scuffed. Drives and runs tight other than the present issue. After getting this worked out I'm going to replace the shocks. Not leaking just a little weak from age. Even an old seldom used vehicle needs work.

I've always been into the older trucks. My last restore was a 1960 F100 - 223. Sold it but wished I hadn't. Trying to pry the 1960 F100 - 292 short wheel base my brother owns away from him. I like that 1957-60 style. I just like simplicity. Can't get no simpler than that except a model A.

 

I assume the fan shroud is in place, it's removal would produce the same results as fan clutch failing to lock.

Your description of temp rising when stopped then going back down to "normal" when moving again is an almost textbook description of failing fan clutch.
Especially if water pump is newer, worn impeller blades can be similar to fan issue.

Fan clutch is heated by the radiator, it has a bi-metal spring on the front that expands when heated, this engages the fan blade more and more so it will spin at water pump pulley speed when rad is hot.

When driving air moves thru rad cooling fins without assistance of fan, but when stopped the fan needs to maintain the air flow or engine temp will rise.

 

Listen to and do what he says when it comes to basics/fundamentals like this; consider it the gold standard, the gospel truth. RonD knows his stuff. What makes him cool is that he didn't tell you which way to fix your problem.

80+k Miles in 14 years is still "to church on sunday" miles to me (with no AC, I can see how it would be a "winter-only" car down in LA). I'm 250+k in the same amount of time...and my old boy keeps on runnin'. It'll be a sad day when he doesn't anymore.

 

Thanks a lot to everyone, especially Ron D for the explanation on the operation of the fan clutch. It isn't just knowing how to fix things but knowing how things works I appreciate the most. After checking the timing I've pretty much resigned to replacing the clutch and obviously the fan because of the cracking going on. I found a place online for a OEM fan clutch at Auto Parts Warehouse. They do PayPal credit which I like.

http://www.autopartswarehouse.com/sh...utch-1987.html

I've heard of Hayden before but not 4 Seasons. About 5 bucks difference. Don't know if there is a quality issue. I guess pretty much everything is made in China.

 

Thank you both for the kind words.

I do believe in the axiom "....if you give a man a fish he is hungry again in an hour; if you teach him to catch a fish you do him a good turn"-Anne Ritchie, 1885(approx.)

And staying with that metaphor, auto repair can be alot like fishing.
We call it Fishing not Catching for a reason, lol, because fishing is an activity that can lead to catching but it isn't a certainty.

The more knowledge you have the better chance you have for the catching part, when fishing or when working on a vehicle.