Overheating Problem

[92bigbko]

Hello BZ.

I have a 92 fullsize 351 6" lift 37" tires. Been sitting for one year before I bought it,

It's running hot after about 15 miles it stays fairly normal then it slowly goes on up last the "L" on "NORMAL" on the guage.

then ya get out and the radiator overflow tub is full and boiling

I put in a new Radiator & Thermostat.

The fan is working good.

 

What else could it be???

All I can think of is the water pump?

could it be the water pump???

<*EDIT*> good point dea bronc. YES I DID FLUSH. the garden hose kind and the fluid kind.

Thanks in advance

 

[Seabronc]

Have you flushed your system? Could be crap in the block causing poor heat transfer.

Good luck,

>-

 

[92bigbko]

edit to 1st post. good point seabronc

Yes i did flush it. still didnt help with the carden hose method... and with the fluid method....

good point...

 

[Yardape]

I would maybe suspect your thermostat. Does it still have a fan shroud? Do you have a body lift?

 

[92bigbko]

On the first post I said

I put in a new Radiator & Thermostat.The fan is working good.

No body lift. Yes fan shroud.

>

 

[walnuts75]

When you put the new thermostat in, did you put it in correctly or did you accidently put it in backwards. Also what kind of thermostat did you put in. Some thermostats take a higher temp for them to open up and maybe you inadverntally got one that is hotter.

 

[JLasvegas]

im leaning towards stuck thermostat, when its running hot feel the top hose to see if it has major pressure, then feel the bottom hose and see if its soft and not as hot

 

[BroncoJoe19]

Well it seems that you hit on all of the parts of the system.

If you have a clutch fan are you sure it is working properly?

there was a thread on here that pretty well discussed clutch fans within the last couple of months.

Is you fan belt tight?

My understanding is that the water pump bearings will go, and start leaking before it will not sufficiently pump.

Although you flushed with a garden hose, that may not have had enough pressure to clear clogged passages.

It is possible that the new thermostat is bad, you may pull it and throw it into a *** of hot water, and measure the temp at which it opens. You may pull it and see if your truck overheats without it. If not, replace it, I wouldn't run without it, or you are likely to burn excessive fuel and possibly burn out your cats.

You may consider taking her to a radiator shop and have the engine block power flushed.

Consider pulling the freeze out plugs, and giving it a good flush.

I don't know if there is a method to clearing a clogged water jacket similar to rodding a radiator, or if it is ever necessary, but this is a question I'd be asking if the problem was mine.

Just trying to stimulate discussion by those who know more than me.

joe

 

[BroncoJoe19]

Had the engine ever been rebuilt?

I found this...

Obstructed coolant passages have created more than their share of headaches for engine

builders. Mass engine rebuilders are sometimes guilty of knocking old freeze plugs into the water

jackets to speed disassembly. Unfortunately, whoever gets this engine after the fact must deal with

overheating issues because those freeze plugs knocked into the jacket obstruct coolant flow and

heat dissipation. During disassembly, take a bright light and inspect cooling passages (water

jackets) for any obstructions and corrosion. Passages between the heads and block sometimes

become clogged with rust and iron particles. Make sure these passages are clear.

 

[Seabronc]

Getting back to one of Yardtape's question on the fan shroud, do you still have one? Removing it makes the system less efficient. My system is so efficient, that the electric fan only has to run less than 5% of the time my engine is running.

>-

 

[92bigbko]

its a carquest 195

 

[Miss Kitten]

i went through the same issue this year

started with a good flush on the system to get all the mud out, still overheated. pull the thermostat completely and still over heated.

then my water pump packed it in. it was the source of all my overheating issues

i have a whole new ball game now as my fan has decided to leave it's assigned area, but that's not for you to worry about lol

i would change the pump out before paying a rad shop to look at it and see if your overheating issues go away

 

[rostheiceman]

how shure are youthe fan clutch is good? if it does not run hot to the point it shuts off after 15min then its not the pump if its on the l in normual the the pump is pumping troubleshoot take the cap off start the truck let it run watch the water you will be able to see when the thromo opens you can also feel the top hose to see to see if water is pumping. with you do all that and everthing seems like all is working shut the truck off and turn the fan it should turn with a little restence if it turn to free its the clutch

 

[92bigbko]

those last two posts were pretty helpful..

the only way i checked the fan clutch is: looking at the fan spinning the speed of the engine..... it just seemed to be locked up like it was blowing hard...

heres the time/guage readings

lol

5 mins-N

7min-M

8min-A

11min-on the end of L...

after 13 mins i always turn it off and let it cool on down.... dont wanna hurt anything....

so i think i will just swap on out that water pump see if that fixes it....

 

[BroncoJoe19]

Miss Kitten,

Just for the sake of storing more fun facts to know and tell,

Did your overheating problem come on rather suddenly, or very gradually over months?

I noted in your postings that your water pump started leaking out the weap hole, prior to your changing it.

How many miles would you estimate did you drive knowing that you had overheating problems before the water pump got bad enough to start leaking?

I'm not being critical of you in any way. I'm just wondering if some kind of general statment can be made like... IF your water pump is going bad enough to allow your truck to overheat, and you aren't sure that is the cause of the problem, just drive it for about 50 or 250 miles, and by then it will be leaking all over the place.

 

[Miss Kitten]

going by miles is a very hard estimate for me to make

you have to remember that my bronco is a trail only rig

so the best that i can say is that i was on three trail runs with it overheating

and when i'm on trail i spent alot of time bouncing off the rev limiter (the new tranny allows me to crawl through more obstacles now)

and that's not even a very accurate account either, cuz now that i know my tranny was shot i could have been having to rev it out alot more due to slipage that i didn't notice with the tranny

sorry i'm a terrible example for overheating issues /emoticons/[email protected] 2x" width="20" height="20" />

 

[92bigbko]

it wasnt bad miss kitten lol.

so ill swap out the water pump then come back here to share with you guys how it goes.

 

[rostheiceman]

ok if your clucth is bad it will still spin just not at the speed it should. with a fan clutch at idle speed it should run with the motor but at hi rpms it should run at about 1500 rpm if the spring is no good it will still spin at idel but at hi rpms it the torqu will be to much for the worn spring and it will only spin at about 500 rpm. because it still spins it will still kindof cool the motorbut not very good. so before you put a new pump on i would change the clutch if it does not fix it you can always take it back un like a pump plus it cost less. i would still go thourgh the troubleshooting i posted before so your not going into it blind. this might sound a little strange but with the troubleshooting after you have checked everything let the truck run and time it from when you start the trucktill it gets hot about half way between the l and the hot line if its the pump it should take about 15 to 17 min if its the fan about 20 25 mins i know it sounds crazy but your truck will shut off before you can do any damage.

 

[BroncoJoe19]

going by miles is a very hard estimate for me to make
you have to remember that my bronco is a trail only rig

so the best that i can say is that i was on three trail runs with it overheating

and when i'm on trail i spent alot of time bouncing off the rev limiter <snip>

Yeah... but it still gives some kind of an idea.

IF we look at it this way... 3 days of trails at 6 hours each (some of the time at idle 700 RPM and some at 2-3,000 RPM average 1400 rpm = equivelent to Idk 40 mph?) so 18 hrs @ 40mph= 720 miles. I suspect those numbers are probably pretty generous, so I guess it could be anywhere from 300 to 900 miles (for a truck running on the street).

Thanks... that gives me a little bit of an idea of how quickly (or not) it will go downhill.