Cooling Guru's, help needed. EFI 5.0 - SOLVED!

[Broncobowsher]

Did you check anything that I listed?

 

[brianstrange]

Did you check anything that I listed?

Yes.
Fan is cutting air away from radiator
Proper rotation fan and pump
Visual flow across the radiator while running / open tstat
I'm currently verifying.... The new radiator only has 8 fins per inch. Radiator specialist said that's the problem (cooling capacity issue) Even though it's a 3 core, not enough heat is being transferred thru. Verifying with a radiator swap.

 

[Pa PITT]

... I'm going to subscribe to this thread so I can see how it comes out..
... I worked on my old BRONCO & never got it to cool. 3 Radiators .. 2 water pumps but not the High Flow pump.Several thermostats All water all Antifreeze and 50/50.. All V Belts.. Timing 40 times .. I never got mine it run cool but .. Fabing up some air dams seem to do more than anything I tried .. I got roofing gutter metal & tin snipes & duck tape too seal .. tried to plug all the holes around the radiator ..Too make all the AIR go through the radiator and not around the side of the radiator ..
... Later I gave up on mine and put in a diesel .. My Diesel will Idles for 45 minutes too get too 180 & I can flip on the cooling fan and It'll drop to 120 or so..
...
..While I worked at Dodge .. look at the 2002 type trucks . See the air dam. Those are designed to push extra air up into the radiator..
.. We always said those trucks had to have them in place .. So with that in mind I tried to get all the air through the radiator ..
... My diesel doesn't even have a fan blade on it.. But I do have a small electric cooling fan. On a Manual switch ..It needs too be on a sensor .. On manual it cools it down too much. I'm running the same $102.00 Aluminum rad I had with the gas 302.

 

[Broncobowsher]

Yes.
Fan is cutting air away from radiator
Proper rotation fan and pump
Visual flow across the radiator while running / open tstat
I'm currently verifying.... The new radiator only has 8 fins per inch. Radiator specialist said that's the problem (cooling capacity issue) Even though it's a 3 core, not enough heat is being transferred thru. Verifying with a radiator swap.

I think you are right. That core sounds undersized and it sounds like you have all the other basics taken care of. Let us know how the better core works out.

 

[toddz69]

Yes. The new radiator only has 8 fins per inch. Radiator specialist said that's the problem (cooling capacity issue) Even though it's a 3 core, not enough heat is being transferred thru. Verifying with a radiator swap.

8 fins per inch?? Good lord - you can probably see right through that radiator. Do us a favor and weigh that thing when it's pulled. I'm curious what it weighs.

A few years ago I had a "cheapie" 3 core that I installed in my truck. I took it out and weighed it - 17 lbs. as I recall. I took it down to my favorite local radiator shop to have a nice proper HD core put in it. When I got it back, I put it on the scale again - 27 lbs. That extra 10 lbs. definitely helped my truck run cooler.

Todd Z.

 

[brianstrange]

6-26 Update: I looked over the engine bay again, checked plugs (white) tested vac lines etc, and may have discovered another issue. While the FP regulator held vacuum on low, the connection at the regulator was allowing air in under high vacuum (testing with my mouth of course) Culprit?

 

[Broncobowsher]

6-26 Update: I looked over the engine bay again, checked plugs (white) tested vac lines etc, and may have discovered another issue. While the FP regulator held vacuum on low, the connection at the regulator was allowing air in under high vacuum (testing with my mouth of course) Culprit?

Doubt it. If anything a loss of vacuum will increase fuel pressure, which is not a source of overheating.

 

[brianstrange]

Doubt it. If anything a loss of vacuum will increase fuel pressure, which is not a source of overheating.

......but it will cause a lean condition with the vacuum leak. I will know for sure on the next hot day

 

[nvrstuk]

You said your plugs were "white". White means you are burning very lean which is very hot... check that out. Vacuum leak will of course make you burn lean. Have you checked your header tube temps? Check with an infared gun as close as possible to the same distance and position of each primary tube.

I'm having cooling issues also on the same engine that never had an issue in it's first 200,000 + miles of life... but I'm not stealing this thread. ;D

 

[dave67fd]

Brian,
Don't know if you investigated the "trapped air" issue but this is one of the major reasons for temperature variances. Air rises to the top of the cooling system and gets trapped, potentially causing the cooling system to vapor lock. When the radiator is made the higher point in the system, the air will escape into the radiator and it will be vented out through the radiator cap and the overflow system. If not it can sit high in the intake area.

Don't know if you have a true recovery system or just an overflow. If just overflow it could also be re-intaking air well after purge.

Other ideas: I know you replaced the thermostat with different temp ones but try different manuf. and make sure it has a relief vent (pretty sure most if not all do).

Does it really go much above 225? or does it hold there? A 15 deg. swing with ~1K RPM increase (especially with the transmission temp increase) isin't overly excessive.

Just some thoughts.

 

[BwoncoHowie]

......but it will cause a lean condition with the vacuum leak. I will know for sure on the next hot day

The lean AF mixture condition will contribute to higher head and valve temps, which will ultimately cause higher engine temps, but I don't think this is the main cause. Getting the AF ratio right will help. I think you still need to explore the cheap radiator issue.

If you are not sure your water pump is the right capicity for the size pulley you are using. There are higher volume pumps available.

For more info go here... http://www.flowkoolerwaterpumps.com/

 

[Broncobowsher]

The miniscule amount of air that could be leaking through the fuel pressure regulator hose won't be distinguishable to the EFI system. Especially at the airflow levels under load where you are having your hot running issues.

Good running EFI engines usually have plugs that come out pretty white. That is a reason they can last 100k miles between changes. I have pulled plenty of plugs that are very white and very old with the electrodes burned away I don't really worry about white plugs that much. You will have detonation issues due to lean before anything else.

 

[bsquared]

I am running a 96 Exploder 5.0L w/ its' original serpentine belt and clutched fan. I opted for a Champion 3 core radiator during the build and have had no cooling issues in 100+ deg Houston weather. I think your radiator guy has a good point.

If you are looking at changing the radiator, the Champion ones see to be a good value, at least to me. Beware -the Champion aluminum 3 core will need the brackets meant for a copper 4 core. It is thicker than a regular 3 core. Best of luck resolving it.

 

[brianstrange]

The miniscule amount of air that could be leaking through the fuel pressure regulator hose won't be distinguishable to the EFI system. Especially at the airflow levels under load where you are having your hot running issues.

Good running EFI engines usually have plugs that come out pretty white. That is a reason they can last 100k miles between changes. I have pulled plenty of plugs that are very white and very old with the electrodes burned away I don't really worry about white plugs that much. You will have detonation issues due to lean before anything else.

Was able to confirm the vacuum leak(s) were non contributing to the overheat issue. Also, as I slowed a bit the temp quickly dropped - possibly confirming the theory of the air passing thru too fast. Next update 1-2 weeks out

 

[zbronco]

I have been fighting similar issues. I was using a dorale electric fan and could run fine at low rpms but at higher rpms my temps would shoot up quickly. i went through my complete cooling system, water pump, thermostat, radiator, hoses, rad cap etc..

I decided it must be an air flow issue and purchased a mark viii fan this week only to find out it would not fit. So I cut out the electric fan and used it as a shroud with the a explorer clutch fan. bronco now idles at 170 and runs at 190 with a/c on in 100 degree temp. I only have limited miles but I am not seeing the same issue I was seeing with the old set up.

I realize our set ups are different but thought it might bee good food for thought.

 

[Larry B]

I had a jeep PU with the rambler 327 V8. The heater quit working and temp would rise when pulled hard. I finally pulled the water pump as last resort and the impeller had came loose off the shaft but still has enough circulation to run. And it never leaked either.
On my daughters 3 leader ford van it started heating also and it was also the impeller but it was a flat plate type with the end plates bent to get flow and they had rusted away to nothing. Not saying this is the problem but both happened to me.

 

[brianstrange]

Well, installed a new radiator with a higher fin count, and she's good to go. 180deg, rises to 190 in heavy traffic, and that's without the shroud. No temp chages now at higher RPM's and speeds. The issue was that the air was passing too fast over the tubes/fins, not allowing enough time for heat transfer. A higher fin count slows the air down.

 

[nvrstuk]

Glad it's working.

My high fin count radiator wouldn't let air pass...Exploder fan / shroud. swapped in a large 460 radiator with same shroud and it's would easily hold a business cards against the grill at idle... too many fins per inch on mine

 

[brianstrange]

Glad it's working.

My high fin count radiator wouldn't let air pass...Exploder fan / shroud. swapped in a large 460 radiator with same shroud and it's would easily hold a business cards against the grill at idle... too many fins per inch on mine

Yes, I was told 12 is ideal, 16 MAX

 

[bmc69]

I have been fighting similar issues. I was using a dorale electric fan and could run fine at low rpms but at higher rpms my temps would shoot up quickly. i went through my complete cooling system, water pump, thermostat, radiator, hoses, rad cap etc..

I decided it must be an air flow issue and purchased a mark viii fan this week only to find out it would not fit. So I cut out the electric fan and used it as a shroud with the a explorer clutch fan. bronco now idles at 170 and runs at 190 with a/c on in 100 degree temp. I only have limited miles but I am not seeing the same issue I was seeing with the old set up.

I realize our set ups are different but thought it might bee good food for thought.

Good food too, methinks. My experiences were quite similar to yours and I ended up about the same place too. My fan and clutch combination is off a late 70s 460 Camper Special pickup though. All the failed electric fan "experiments" are still in a pile on a shelf in the shop somewhere.