Gradually rising temperature

B-Co Kid · Jul 27, 2014

1987 B-Co, 351w, edelbrock 1406, edelbrock performer intake, gibson headers, c6 trans, no EEC (from factory), stock fan w/shroud in place, newish radiator, fairly new fan clutch. (radiator has been recently fully flushed, reflushed, and filled)

So, the temperature gauge rises gradually while in gear. Thinking it might be timing related, Ive done several test runs

ranging from 16 degree btdc to 6 degrees btdc, and the problem still occurs. and what I mean is, that when I put it in gear, with brake engaged, and sit for about 5 mins in gear, the temperature gradually rises (to the L in NORMAL on the gauge). Once I start driving for a while, the temp drops back to normal (between the R and the M in NORMAL on the gauge). im pretty sure that the timing is not the problem. Other problem factors that ive considered are: the heat generated from the shorty headers, the thermostat, the heater core is not connected, and the engine has been bored .060. any help would be greatly appreciated...!!

miesk5 · Jul 28, 2014

yo B,

This is by Ford for a 96, but same for your year;

Engine Overheats

Damaged water thermostat.
Damaged water pump.
Cooling fan inoperative.
Plugged radiator.

GO to Pinpoint Test B

read more incl. Test B at http://www.diesel-dave.com/vehic/manual/stj/stj33013.htm#b

Coolant Temp Gauge & Sender Testing; "...Pull the Red/White wire off the sender (it is the push-pull type connector) ; ground it to the block, intake, or head (have a good jumper wire ready if needed)

turn the key to RUN

If the needle pegs to Hot, replace the sender.

If not, circuit diagnosis is next.

Modified from Seabronc's & BLADE262US's reply @ http://broncozone.com/topic/10973-temp-gauge-testing/

Read more except for the resistance tests that are for a 96; have to find specs for your year

Rons beast · Jul 28, 2014

Hey kid,

Read all that M5 posted. But remember when the Bronc is sitting still the only air through the radiator and over the engine is being pulled by the fan. It is not the most efficient, but the only method provided to cool the engine.

Your engine is larger than stock, and running headers. This adds to the under hood heat.

You didn't mention the Tstadt temp you're running, ( I'm using a 160 here in Fla.) You could also consider an electric fan. They are somewhat more effecient.

I believe your problem is simply one of displacing heat, not any engine malfunction.

Good luck

nelbur · Jul 28, 2014

The problem could be from a marginal radiator, either due to junk in the fins which can be sprayed out backwards using a garden hose, or from deposits inside, which a radiator shop can take care of. It could also be from a sticky thermostat. They can start opening slowly and give a high reading before setteling down. When I see this happening I buy a new thermostat and look for a good day to replace the old one. I currently have a new thermostat and am looking for a cool day.

Seabronc · Jul 28, 2014

Could possibly need a good engine cooling system flush.

>-

B-Co Kid · Jul 29, 2014

The radiator was professionally cleaned a while ago, and the engine hasn't seen very many miles. But I recently flushed it twice. The coolant was bright green and there was no debris in the old coolant. haven't tried ******* the gauge yet, I will try that next. I did purchase a "fail safe" tstat rated at 195 degrees that i am waiting to install if no other options solve my problem. the tstat currently installed is a stock spec tstat, whatever that rating is. If the gauge is operating ok, I was considering wrapping the headers with the thermoshield stuff, and if that doesn't help, I will replace the tstat. Thanks for the help guys, any other suggestions would be appreciated. By the way, I'm seeing mixed opinions about wrapping the headers. Is this a good or bad decision??

miesk5 · Jul 29, 2014

yo B,

Did you go through Test B yet?

read more incl. Test B at http://www.diesel-da.../stj33013.htm#b

Allow engine to run for 10 minutes.
Feel the inlet and outlet heater water hose and the underside of the upper radiator hose.

Are the upper radiator hose and heater water hoses cold?
Yes - REPLACE water thermostat. REFER to Thermostat, Water in the Removal and Installation portion of this section. RETEST system
LEAVE engine RUNNING. GO to B5

B5 CHECK COOLING FAN

Check for proper cooling fan clutch operation. Perform Fan Clutch Test. Refer to Component Tests in this section.

Did cooling fan clutch operate OK?
Yes - CHECK the following:

Rust or scale in radiator
Water pump shaft and impeller
Collapsed lower hose

NO - REPLACE fan clutch. REFER to Cooling Fan Blade and Fan Clutch in the Removal and Installation portion of this section. RETEST system.

B-Co Kid · Jul 29, 2014

The heater has been disconnected. The radiator hose does get hot once the engine reaches operating temp. I have not performed the fan clutch test yet. I may try that tomorrow, but the fan clutch is new

Rons beast · Jul 30, 2014

Hey Kid,

I for one like the idea of wrapping headers...especially in a tight engine compartment.

I don't think having the temp gauge at the "L" when just sitting at idle is really too hot. Especially with a 195 tstadt. If it should continue to climb I would be concerned.

Just my opinion.

What does the temp do if you raise the engine speed in park to say 1500?

B-Co Kid · Jul 30, 2014

The tstat currently installed is the oem spec, I haven't installed the 195 degree yet. And the temp gauge has crept past the L when doing my tests. I'm sure it would have continued to rise if I left it in drive to see how far it would go. With the engine running and trans in park, the gauge stays in its normal range. It's only when the engine is running and the trans in gear and at a standstill that I experience the problem. When starting cold, the rpms are at 1500 until it warms up, and then drops to about 900-1000. Doesn't run hot, temp gauge does t rise, it's steady. Again, the only time I notice the temp gauge moving up to overheating is in gear and at a standstill

Rons beast · Jul 30, 2014

Unless I missed it you don,t have an external tranny cooler. I would consider one

Again just my opinion. I'm in the heat of Fla. (96deg.) today, and I sometimes see my gauge creep toward the "L" if I'm in traffic a long time. Good luck

miesk5 · Jul 31, 2014

yo,

Instead of the fan clutch test, just have a helper watch to see if fan stops spinning or visibly slows down when in gear & running and temp gauge begins its creep upward. Watch helper & ensure they don't lean over belt, pulleys and fan. Ask if they hear a squeal from belt/pulley areas, etc.

Those RPMs appear to be high at 900-1000

B-Co Kid · Jul 31, 2014

when it rains it pours..so when i started to get back on this heating today, I go to crank the engine over, and it wont start. It turns over, but will not crank. From my preliminary tests on this problem, I am not getting spark at the plugs or coil. I am getting voltage to the coil from the wiring, but not spark at the plug wire. When I press the throttle, there is gas that squirts into the carb, so im sure its not fuel related. The last timing was set at about 14 degrees btdc when I was checking the overheating problem. Will timing that is to advanced cause no spark?? my problems seems to come in twos.. please help!!

Rons beast · Jul 31, 2014

Hey Kid,

Sorry to hear you have yet another problem. The timing will not cause a no spark condition. Connect a test light between the + and _ terminals of the coil! and crank the engine. If the light flashes, you are getting a signal to the coil. The coil or the coil wire would be suspect. No flashing light would indicate a problem with the primary ignition ...module, pick up coil, or related wiring.

Good luck

B-Co Kid · Jul 31, 2014

I will perform that test light check tomorrow and post results. Thanks!!

B-Co Kid · Aug 3, 2014

the no spark issue was because one of the ignition module came loose :glare: . now back to overheating problem

miesk5 · Aug 4, 2014

yo B,

Do you have air conditioning in the Bronco?

If so, check condenser for blockage that will reduce air flow through rad.

Is it still a TGI ignition exc for MSD coil and Cap?

14 deg timing... is that as spec by Ford?

COOLING SYSTEM TROUBLESHOOTING

High Gauge Reading

AAAAAAAAA COOLING SYSTEM TROUBLESHOOTING.pdf

EDIT; I ADDED FOLLOWING @0936 hrs today; 4 AUG 2014

Think air is trapped in Cooling System?

Burp it

B-Co Kid · Aug 9, 2014

Air conditioning system was removed long ago. If you mean a TFI ignition, no it is a duraspark II ignition. I think the factory spec for timing is 10-12 degrees, and I only had it set at 14 degrees because I was checking a range of timing setting to see if the overheating was related to timing. The last setting was at 14 degrees before i had the no start issue. It is now at10 degrees. I lowered the throttle setting to 950 rpm in park and 750-800 rpm in drive based on your suggestion. I will check the overheating issue again today to see if the throttle adjustment helped. Im guessing my problem is just the heat generated by the headers as ron suggested. HOW DO YOU BURP THE COOLING SYSTEM??

Rons beast · Aug 9, 2014

Hey KId,

Easiest way to burb the cooling system is to park on a grade, or jack up the front end so the rad cap is at the highest point of the engine bay.

Block wheels and set the parking brake to be safe.

Take the cap off the rad. Run the engine at idle, in park. If the tstadt is opening correctly the coolent should circulate and any air will rise to the highest point, ( the top of the rad) and be expelled. DO NOT put your face over the rad opening.

Are you heater hoses looped or are they capped at the heater core? If it's the latter that could be where the air is trapped.

Good Luck

Gradually rising temperature

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