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Old Sep 5, 2008 | 11:15 PM
  #1  
fordtrucksj's Avatar
fordtrucksj
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Question Mystery Overheating

89 B2, 4X4, 2.9 L, 5 speed, JBA headers & wire set, Jet power chip, Fram Air Hog, new radiator, water pump, new engine (less than 10000), thermostat, (in a nut shell--it was a complete body off rebuild--so new everything). I've been driving it since August of 2007 (one year) and only in the last 2 - 3 months it has been running a bit hot--just over the middle mark to the 3/4 mark. It has radiator fluid, no leaks that I can see, the level stays steady, no weird noises etc. Well, maybe when I turn on the AC--every now and again it makes a screach noise like when the belt is too lose, but I've tightened it. Any ideas? Is it posible it's only a short in the gauge? Things to check? Oh yeah, one last thing that just started about 2 weeks ago, when I first start it up, it idles a bit high--at about 1000 - 1100 RPM until it warms up and then drops to under 1000 RPMs. Related? Maybe?
 
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Old Sep 6, 2008 | 03:11 AM
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> just over the middle mark to the 3/4 mark

Way too hot for one with a new radiator. As long as the shroud is there and this problem just started, I would look at the clutch fan being defective.
 
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Old Sep 6, 2008 | 08:36 AM
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Gotta agree with Rebocardo.

General question. Does it get a whisker hotter while driving through town? As in really starts going into that danger zone? (on a 2.9 it seems...anything over middle mark could almost be considered a danger zone) If it runs nice and cool running 60 down the highway, with the A/C on? And once you get it into town it starts climbing up a wee bit faster then we'd like to see? Normally points right at that fan clutch. When it starts to crap? It can't spin the fan fast enough to cool things down.

With a 2.9...let's see if we can get this figured out before the heads crack.

S-
 
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Old Sep 6, 2008 | 09:02 AM
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These 2.9's ran hot when they were new, several years old...all the time. It was a major complaint from customers back then.

Ford only lists one t/stat for these engines...197 degrees. What we used to do was drill a small hole in the t/stat...that seemed to help.

You can also use a cooler thermostat from a 302 (180 or 160), but you'll have to trim the edge so it will fit into the housing...that's another thing we used to do.

btw: Are you sure you installed the t/stat correctly? The element faces towards the engine.
 
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Old Sep 14, 2008 | 02:04 AM
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Mystery Overheating

Originally Posted by rebocardo
> just over the middle mark to the 3/4 mark

Way too hot for one with a new radiator. As long as the shroud is there and this problem just started, I would look at the clutch fan being defective.
Well, I just replaced the fan clutch just so I could rule it out completely--and the problem is still there. It runs just below middle and during prolonged driving (20 minutes +), the needle goes to middle and as soon as I hit the AC, freeway or city--it runs to 3/4 of the way on the gauge. I'm getting pretty frustrated with it.
 
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Old Sep 14, 2008 | 02:06 AM
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Overheating

Originally Posted by NumberDummy
These 2.9's ran hot when they were new, several years old...all the time. It was a major complaint from customers back then.

Ford only lists one t/stat for these engines...197 degrees. What we used to do was drill a small hole in the t/stat...that seemed to help.

You can also use a cooler thermostat from a 302 (180 or 160), but you'll have to trim the edge so it will fit into the housing...that's another thing we used to do.

btw: Are you sure you installed the t/stat correctly? The element faces towards the engine.
Well, I have done this repair a few times over the last 13 years, but I guess it's always possible. If I recall, it can only fit in one direction--is that right? Other ideas?
 
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Old Sep 14, 2008 | 02:11 AM
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overheating

Originally Posted by Tedybear
Gotta agree with Rebocardo.

General question. Does it get a whisker hotter while driving through town? As in really starts going into that danger zone? (on a 2.9 it seems...anything over middle mark could almost be considered a danger zone) If it runs nice and cool running 60 down the highway, with the A/C on? And once you get it into town it starts climbing up a wee bit faster then we'd like to see? Normally points right at that fan clutch. When it starts to crap? It can't spin the fan fast enough to cool things down.

With a 2.9...let's see if we can get this figured out before the heads crack.

S-
Yes, it does. Never goes past the 3/4 point. I replaced the fan clutch so that I can rule it out completely and it still overheating. Other possibilities? At this point I am considering all ideas--especially if people have gone through this and with a 2.9 it is likely. I have a couple of questions--Do you think the Jet Power Chip might be causing this? Since it is a completely new rebuild, it has had the power chip since I first started her for the first time since the rebuild. Second question is, would the timing being off cause this much over heating? I ask because it idles just a weee bit too high at about 1000 to 1100 RPM, but eventually when it warms up and I've been running it, the idle RPM lowers to about 850 to 900. Thought?
 
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Old Sep 14, 2008 | 06:54 AM
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The factory guages are also known to give false info.
OR do you have after market mechnical guages?

could be the temperature sending unit is on its way out.

If it Idles high then be looking into the temp sensor for the computer ,(not dash gauge). the TPS, O2 sensor, and or the AIC. Certainly look over the vacuum lines.

Does it Idle high always or just when warm or cold?

Have you tried to get the codes??
 
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Old Sep 14, 2008 | 09:30 AM
  #9  
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> Do you think the Jet Power Chip might be causing this

I doubt it because we would have seen people post about it in other forums a long time ago.

> I just replaced the fan clutch just so I could rule it out completely

Just for giggles, see if it spins freely while cold, then go heat it up, shut the engine off and see how it spins.

As long as the noise will not bother people, drop the cats at the Y pipe. Run it at high idle (2K) or drive it a short distance. A clogged cat. converter will surely overheat an engine. The way to tell is by reving it. If it is kind of slow with the cats and then without it pegs to 4K easy, the cats are clogged.

Exhaust pressure testers are kind of expensive to buy and I do not think they rent them.

After market cats are generally junk for most cars. If you can, a junkyard F-150 will work if you want to weld it in. Or buy a generic one with a 2.25 inlet.
 
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Old Sep 14, 2008 | 02:24 PM
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gauges

Originally Posted by enriched&beyound
The factory guages are also known to give false info.
OR do you have after market mechnical guages?

could be the temperature sending unit is on its way out.

If it Idles high then be looking into the temp sensor for the computer ,(not dash gauge). the TPS, O2 sensor, and or the AIC. Certainly look over the vacuum lines.

Does it Idle high always or just when warm or cold?

Have you tried to get the codes??
The gauges are stock. Is the temp sensor the one that goes mounted on the thermostat housing? If it is, it's also new--I suppose it could have been defective, but otherwise it is new. The TPS, O2, and the AIC are also new. Thoughts? I replaced them when I did my build.
 
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Old Sep 14, 2008 | 02:27 PM
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overheating / exhaust

Originally Posted by rebocardo
> Do you think the Jet Power Chip might be causing this

I doubt it because we would have seen people post about it in other forums a long time ago.

> I just replaced the fan clutch just so I could rule it out completely

Just for giggles, see if it spins freely while cold, then go heat it up, shut the engine off and see how it spins.

As long as the noise will not bother people, drop the cats at the Y pipe. Run it at high idle (2K) or drive it a short distance. A clogged cat. converter will surely overheat an engine. The way to tell is by reving it. If it is kind of slow with the cats and then without it pegs to 4K easy, the cats are clogged.

Exhaust pressure testers are kind of expensive to buy and I do not think they rent them.

After market cats are generally junk for most cars. If you can, a junkyard F-150 will work if you want to weld it in. Or buy a generic one with a 2.25 inlet.
The entire exhaust is new. I am running Titanium JBA headers, new Y pipe, exhaust with a new Cat and muffler all the way back. What I did notice is that the discoloration in the Y pipe seems / looks unusual. Sort of blotchy heated looking. Maybe I can take it back to the muffler shop to verify that the Cat is not clogged, but it is new--1 year old.
 
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Old Sep 14, 2008 | 02:41 PM
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There has been good advice here but first as I always do in a customer complaint of over heating is find a point and shoot temp gun or other means to make sure its getting hot. On some Ford gauges have seen voltage increase from alt curcuit move them up.
I noted your location but has it been getting cooler there recently to account for the higher start up idle?
 
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Old Sep 21, 2008 | 12:38 AM
  #13  
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Overheating

Originally Posted by Orin Martin
There has been good advice here but first as I always do in a customer complaint of over heating is find a point and shoot temp gun or other means to make sure its getting hot. On some Ford gauges have seen voltage increase from alt curcuit move them up.
I noted your location but has it been getting cooler there recently to account for the higher start up idle?
Thanks Orin. The temp here in Brentwood CA has been pretty steady--HOT--95 - 105, though it has begun to cool, but it's still in the high 80s low 90s. I am going to check the engine with the temp gauge / meter after running it for 10 minutes or so and see what the numbers look like. Thanks again.
 
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