Weird cooling on my 84 D150

-
4spdragtop

4spdragtop

FABO Gold Member
FABO Gold Member
Joined
Aug 28, 2009
Messages
39,390
Reaction score
22,632
Location
Ontario Parts Unknown
So 84 D150 with 360, my DD. Drove home last night..approx. 5 hours, truck would barely warm up at times. Sometimes temp guage would be 1/2 way, sometimes 1/4. In the past few weeks, at times it would overheat while idling OR after a restart. For example I drive to gas station, fuel up and then turn key fwd and the gauge is pegged to the top AND when I start it steams from under the hood. Coolant protection is about -25*C, I know its not near enough, and Im strengthening it today.

About a month ago the lower rad hose blew off the rad. I pulled over and was able to get the hose back on and the rad topped up with water(all I had and about 10 at night). Truck kept overheating HUGE the 5 miles home. I had to stop about 3 times. Next day I replaced the lower rad hose and added coolant. Maybe not quite enough, approx. -20*C protection. I also bought a t-stat, but didn't replace it for a bit. Both prior to and after changing t-stat the symptoms are the same.
So new t-stat, new coolant to approx. -25*C, and new lower rad hose. Rad looks fairly new and the previous owner told me it was new, so Im guessing maybe 3 years old at most??
Any ideas??

Thanks all
 
If you rev it, does the bottom hose collapse?

With it running, warmed up and the cap off, do you see movement across the tubes?
 
Bad Sport said:
If you rev it, does the bottom hose collapse?

With it running, warmed up and the cap off, do you see movement across the tubes?
Click to expand...

I just went out and fired it up...its still cold, but bottom hose didn't collapse. Cap is off and I will check again once truck is warmed up.
 
Check the bottom hose again after the stat opens, and you put the cap back on.

I see you replaced the bottom hose. Did it have a spring in it?

Anymore, when I replace one, if it didn't come with a spring I make a coil out of a wire coat hanger and put it in there before I install it.
 
I've had heater hoses freeze up on me when in a situation similar to yours and I had to temporarily get by with added water. Even though I added antifreeze later to get back to having a correct mix, it took weeks before a proper thaw allowed the new coolant through the heater hoses. That would explain a lack of heat inside the cab. If there is observable flow in the radiator then I'd suspect a faulty temperature gauge combined with frozen heater hoses/heater core.
 
thermostat sticking

I have gotten 2 bad ones in a row brand new. check them in a pot of boiling water to make sure its working before you put it in
 
Bad Sport said:
Check the bottom hose again after the stat opens, and you put the cap back on.

I see you replaced the bottom hose. Did it have a spring in it?

Anymore, when I replace one, if it didn't come with a spring I make a coil out of a wire coat hanger and put it in there before I install it.
Click to expand...


Ok, checked gauge and its 1/2. Revved up with cap off, no bubbles/flow that I could see across the neck of rad. Put cap on revved up and no collapse on lower rad hose(no spring either). I used my temp reader(owned for over a year and finally get to use it) upper rad hose was high 50's *C and the lower rad hose is high teens??
Thermostat is a 195

Yeah as soon as you mentioned the spring in the hose its like DOH:violent1: I should checked before I bought it.....old age

Here's pics....I know stupid question, but is my coolant temp the one with the 3 hoses coming off of it mounted on the upper rad hose union?? OR is it the one with the white zip tie??

Thanks Bruce
 

Attachments

  • 20150228_160944.jpg
    43.6 KB · Views: 132
  • 20150228_161100.jpg
    47.4 KB · Views: 129
Yep I shoulda checked/boiled the t-stat...old age again! BUT I did drill a bypass hole in it. I didn't use any RTV, just the gasket. Ive heard these trucks run cool, but the steaming up and pegged gauge is new and weird.

So what is the piece that is located in the upper rad hose union??

Thanks all!
 
I've taken a few water pumps out of their housings before and found bad impellers. Either loose on the shaft or impellers nearly worn down to nothing. It may not be the most likely cause but I wouldn't rule it out.
 
1967 'cuda said:
I've taken a few water pumps out of their housings before and found bad impellers. Either loose on the shaft or impellers nearly worn down to nothing. It may not be the most likely cause but I wouldn't rule it out.
Click to expand...

I have a 70 and up style alum water pump...I wonder if there is any difference between the 2??(unknown origin on the 70 and up style)
 
The coolant sensor doesnt use an electrical coonection?? There are only 2 vacuum lines that I can see
 
My guess is the impellers on the water pump and shot, or you have a bad clog in the system.

I actually froze my *** off one winter when I was younger,hardly no heat, come spring time the car, the car started running hot.
The impellers had rusted off the water pump, this was with a slant 6.
 
There was a thread a while back where the water pump impeller was loose from the shaft and it would spin by hand. Not loose enough to come off, but loose enough to turn on the shaft by hand. It would slip when trying to pump water....
 
krazykuda said:
There was a thread a while back where the water pump impeller was loose from the shaft and it would spin by hand. Not loose enough to come off, but loose enough to turn on the shaft by hand. It would slip when trying to pump water....
Click to expand...

I remember that thread, seems the guy was chasing the problem for a couple of years.
 
Good points with the impeller. Would a 70 up alum pump be the same? I have one but my truck is ac. If it will work where can I get a rebuild kit?
 
4spdragtop said:
Good points with the impeller. Would a 70 up alum pump be the same? I have one but my truck is ac. If it will work where can I get a rebuild kit?
Click to expand...

ok Steve I know it sucks but , i would get to work , pop out that thermostat , stick it in boiling water and make sure its functioning right so you can put that to bed. I had a new thermostat stick closed, water temp immediately came up and had to shut the car off. jumped in the G6 , went and bought another 3 dollar 180 degree Stant thermostat. this time I could actually see the gauge start to come up and then go back down fluctuating, giving me little to no heat after 1/2 hour of running. jumped back in the G6 and went and bought ANOTHER one , this time I spent $9.00 on a "nascar" thermostat, dropped it in a pan of boiling water, it worked great and finally everything was back to normal, it opened and closed as it should. I tested the other 2 and they were AFU'd . I only wish I had checked them previously before I went through all the bs . I have heard plenty of stories about the Stant thermostats being junk out of the box.
now , yours may work , but you don't really know unless you can physically SEE it open and close. I always use a 180* in my engines. if you verify that it is in fact working, then you can move on to other possible issues. I just hate to see you chase your tail if it is in fact a bad stat. that's my story LOL
 
I will pick up a new one tomorrow and pull the one I just installed and test them both. Not much sense guessing anymore.
Thanks all!
 
All the ideas about water pumps and caps and hoses are fun, and hopefully one of those guesses IS it.

However, being that it has a new radiator and a radiator hose blew off, I'm suspecting it has a weak head gasket or a cracked head. When combustion gasses or air gets in the cooling system, it causes air or steam pockets to form which screws with the gauge and then causes the thermostat to close when it shouldn't. It also pressurizes the cooling system excessively.

Hopefully that ISN'T it, but if thermostat and radiator cap(the #1 most blamed item for any cooling system problem) don't cure it and you have another attack of severe overheating or something blows off again, then you'll have to pressure-test the cooling system or sniff it for combustion gas.
 
4spdragtop said:
Good points with the impeller. Would a 70 up alum pump be the same? I have one but my truck is ac. If it will work where can I get a rebuild kit?
Click to expand...


A while back Mancini was selling brand new aluminum water pumps for $45.

Any 70 and up aluminum pump will work. The more blades on the impeller the better, I believe that the a/c cars had more fins on the impellers than non a/c cars...

But either will still cool your truck...
 
You must log in or register to reply here.
-

Back
Top