Overheating at idle

[theogre5150]

Ok. So I have done everything I can think of to keep my engine cool. The temp is fine while driving but if I idle for a little while, the temp begins to rise. For example, over the weekend I was picking up some shrub clippings and throwing them in the bed of my truck. I left it idling while I did this and it was not that hot outside. Probably in the low 90's. It took me about 20 minutes to get all of the stuff picked up. By the time I went to unload the truck my temp gauge had moved 3/4 towards H. When I drove off it spiked to H. I parked the truck and popped the hood. I could see the gas boiling out of my inline filter.

Here is what I have done up until this point:

New radiator - 2 rail
New Cap - 7 lbs (I was using 14 lb caps but for some reason I kept popping the seams out of radiators)
New thermostat - 160 deg
New radiator fan - Replaced original 4 blade with a 6 blade flex fan

The gauge is electrical and came out of a F600. It's possible that this gauge is not calibrated for my truck. I do notice on occasion that both my gas and temp gauge will spike at times but go right back down. That tells me that I might have an issue with the voltage regulator. I thought about switching to a mechanical gauge, but if I am going to do that I am going to replace all of my gauges and I do not have the money for that right now.

Here is a pic of my setup. I am generating more heat since I rebuilt everything. New intake and exhaust setup. Here is a pic.


Any help will be greatly appreciated.

Thanks,
Eric

[fordman]

since ythre 6 cyl dotn have shrouds. how close to the radiator is the fan blades? they should be as close as possible to keep the air flowing through the radiator.

[theogre5150]

If I had to guess it would be less than 3 inches of space.

[fordman]

loose fan belt from your other post about the bird chirping.

[fastEdsel]

When you say "2 rail rad" is that just a radiator that is a 2 core? When we get our rads rebuilt, we always have them built as a "4 core rad." Lots of volume and cooling space. The other thing is sometimes on the sixes, when they get warm, the drive shaft on the water pump will actually spin inside the cast impeller. The cast expands faster than the steel shaft and if they are getting on in miles it might be something to check. The only way to check it out of the engine, that I know of, is to boil it in a pail of water then quickly and carefully remove it with insulated gloves etc. and see if the impeller spins when you hold the drive shaft securely. I suppose taking it to a shop to check the integrity of how secure the impeller is to the shaft and clearance between the impeller and housing would be another way. That would be where I would start looking is at the water pump.

[Alvin in AZ]

What is your ignition timing set at? :)

Do yourself and the engine a big favor get that stinkin 160F thermostat
out of there and put a 192 or 195F thermostat back in it. Less wear with
a higher temperature, believe it or not, also more power and better gas
mileage too. No kidding. Strange but true.

Alvin in AZ

[papabug71]

I would imagine its the water pump. In regards to your bird chirping thread earlier, it very well could be the pump making that noise. I just replaced mine on my 01 Dodge & it was making a high pitched squeal sound. The bearing had froze up on it & it was cutting into the shaft. Its poss. that the pump shaft is spinning & the impeller is not. Open the rad. & start the truck. Let it idle & see if the water is mooving in the rad.

I think the 180* stats are a happy medium.

[lee_ford]

theogre5150,
I did a little reading of some of your past threads and I have bad news.

First I found this…

Oh yeah...I forgot to mention that sometimes when I turn the truck off, it has trouble shutting off. It will spit and sputter and then shut off. Don't know if this is related.

That sounds like “Dieseling.” This is caused by at least one cylinder getting hot enough to ignite the gasoline without a spark. A sure sign that at least one cylinder is not getting enough water.

Also this…

...As soon as I climb the slightest hill my truck almost dies on me...

Sounds to me like the back cylinder or cylinders are getting so hot that the fuel is igniting as it enters the cylinder while the valve is still open. This causes a back pressure in the manifold which briefly stops the carburetors air flow and robs all the other cylinders of a good air fuel mixture.

OK, So my question is, when you rebuilt the motor, did you put the head gasket on right?

Here is why I ask that:
Your motor may not be moving the water around inside ALL the motor equally. Water will take the path of least resistance and motor designers years ago learned they needed to slow the water down through the water passages near the pump in order to get it to flow through ALL the motor. The end of the gasket marked “front” will have smaller water holes or passages in order to force the water to the back of the motor. If on backwards, the water in the back moves really slow and lets everything back there get REALLY hot. When driven right after a long idle that REALLY HOT water in the back will mix with the cooler (not really hot) water in the front and get all the water hotter.

The only FIX, is to replace the head gasket and this time put it on right. Do not try to reuse it, buy a new one.

Even if you feel you can live with this condition, the motor can not, so get it fixed. On a long drive the back cylinders will be getting a lot hotter than the front ones and this can cause other things to go wrong. A cracked block, warped head, burnt valves, scored cylinders, melted pistons tops are just a few of the headaches just waiting to happen. Do NOT blow it off.

If you did not know to look for the “Front” mark on the head gasket, you had a 50:50 chance to get it right. But with all the problems you are having, I would bet this is your problem. If I have still not convinced you then find a way to check the temp at both the back and front of the motor. You could use an inferred reader like guys at the track point at the pavement to get track temp or figure out how to mount two sending units and two gauges. Sadly though, I know I am right.

Lee

[theogre5150]

I never update my previous posts so I apologize on that. I no longer have issues with dieseling. I switched to 89 octane and the problem went away instantly. Also, my power is now restored. I think a lot of those issues had to do with my 2bbl sitting on top of a 4bbl manifold. I didn't have the correct adapter between the two. I purchase a 2bbl to 4bbl phenolic spacer and this closed off those back ports. Now instead of feeding the dual port manifold, I'm only feeding the front ports.

I had a mechanic put the engine back together so I do not know about the head gasket. That sucks about the water pump if that's it. I replaced it during the rebuild as well. It's a 2 core rad.

[lee_ford]

I had a mechanic put the engine back together so I do not know about the head gasket.

I would bet money he got it right. The symptoms you posted pointed to a backwards head gasket. Glad that was not it, but I had no way of knowing you had fixed those other issues and felt I needed to let you know.

The cooling issue may be related to the flex fan upgrade. Adding a spacer between the pump and fan will move the fan closer to the radiator and help move air when sitting. Also, if you still have the old fan, you might try putting it back on. Then do a test.

A flex fan is nice if you are looking to get every horse you can out of a motor. But for every day street use, they do not move enough air to do the job needed. This is why you see people adding extra electric automatic pusher fans to Street rods. They will not drain HP but still move the air good at a stop light.

Those flex fans SOUND like a good idea and while they drain less horsepower when turning fast, they move less air at idle. Look at the ends of the blades. Most flex fan blades taper to small tips and the stock fan is the same all the way to the end of each blade. This makes a lot of difference even if they add 2 more blades.

Lee

[george worley]

That gas boiling in the filter with the engine off may be caused by a heat soak(no air moving under hood). Is it throwing out water from the over flow? If It is you may need a higher psi cap. Your rad. that split may have been old or weak. if you can find someone with one of those temperature guns that you point at a area and it gives you the reading that should help you find out how hot it is at the head,top and bottom of rad and any other place. I have found that stock sending units and gauges can be inaccurate. Also check your instrument voltage regulator

[NM5K]

New radiator - 2 rail
New Cap - 7 lbs (I was using 14 lb caps but for some reason I kept popping the seams out of radiators)
New thermostat - 160 deg
New radiator fan - Replaced original 4 blade with a 6 blade flex fan

Just a few comments..
The 7 lb cap is too low. I went through the same thing with new radiators
bulging out and popping the seams. But this is a radiator design problem, not
undue pressure. The last one I got, "I have a lifetime warranty", they seemed to
have fixed the problem. I bet they have been seeing a lot of this with that particular
radiator. The "fix" was to dent in the flange around that problem area, so to make it
stronger and much less likely to be able to push outwards. I almost bet yours was about
in the same spot. On the front seam, a bit left of the middle?
Course, it's possible the inward dent of the flange might be a fluke, but it was in
the exact spot both mine pushed out and broke the solder seal. Anyway, you could
push a dent in that flange yourself to help avoid the outward push.
You really should have a 13 lb or so cap. I think that is about the standard.

The 160 degree stat is way too low. I would change back to the stock 195 degree
stat myself. There is no logical good reason to use a lower temp stat
on a daily driver vehicle. The engineers chose 195 degrees for several
good reasons.

And yep, it's quite possible the flex fan may be the problem if it doesn't move
enough air at idle, low rpm's.
You might try sticking the original fan back on and see what happens.
On mine, I use the original fan, and no shroud and mine never overheats at
any speed. And I'm also using the six banger 2 row radiator.

[lee_ford]

I never update my previous posts so I apologize on that.

Apology accepted. It would help anyone searching for answers to those type problems if you did update that thread.

And of course let us know what you find helps with the overheating at idle problem in this thread.

Lee

[steveh]

Run lean at idle can alos casue overheating. Have you checked the fuel ratio at idle????

Steve

[ROBT257]

I'm currently running in the 220 degrees area. Is this too High?