Gain extra benefits by becoming a Supporting Member Click here find out how!

Classic Performance Products Classic Industries
American Auto Wire
Danchuk Catalog
Hellwig Products IncPerformance Rod & CustomNu-Relics Power Windows



Username Post: 92 K2500 5.7 overheats sitting in gear.        (Topic#363927)
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-09-21 09:02 PM - Post#2811741    

My 92 k2500 4x4 with a 5.7 l and 4L80E is overheating while sitting in gear. I rebuilt the transmission,after no heat in cab and cooked tranny. I flushed the heater core,changed the thermostat and water pump and have been burping it for a week,even on stands. It still keeps overheating in gear. No water in oil,I get heat in the cab again,I replaced the exhaust manifold gaskets last year,I can't see any leaks anywhere,the return hose from the heater core gets warm and the thermostat is opening and pushing coolant through. When it cools and I squeeze the top rad hose with the rad cap on,I can here a click from the bottom washer on the cap,anyone know if that indicates a faulty rad cap?



 
CowboyTrukr 
"10th Year" Silver Supporting Member
Posts: 4543
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
01-09-21 11:27 PM - Post#2811754    
    In response to realroamer

How old is the radiator?

Greg

‘01 Silverado 2500HD 8.1/Allison 1000 Xcab/LB
'00 Explorer XLT 4.0 SOHC V6 Auto
'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500 SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2608
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
01-11-21 04:42 AM - Post#2811826    
    In response to realroamer

Regarding your question about the rad cap being faulty. Does the upper hose become pressurized? Still though, shouldn't overheat sitting (idling) in gear. You say coolant flows through the rad....how well does it flow through? Sounds like the rad needs replacing/professional flush if all else has checked out.



 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-11-21 08:39 PM - Post#2811893    
    In response to CowboyTrukr

I had it 6yrs so I assume original in it.



 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-11-21 08:40 PM - Post#2811894    
    In response to scrambldcj8

I swapped a new rad cap today and it still overheats.




 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-11-21 08:44 PM - Post#2811895    
    In response to realroamer

I got a used waterpump and came with a fan,the pump is good,pully alright,no leaks or noise,but I'm wondering if the fans on these trucks can make it overheat and if it's worth just putting the old fan onto this waterpump?



 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-11-21 08:48 PM - Post#2811896    
    In response to CowboyTrukr

I only flushed the heater core and refilled the coolant and burped it.
How can I tell if I can flush the rad or buy another one?



 
454cid 
Valued Contributor
Posts: 3189

Age: 47
Loc: West Michigan
Reg: 02-18-12
01-12-21 01:20 AM - Post#2811900    
    In response to realroamer

  • realroamer Said:
I got a used waterpump and came with a fan,the pump is good,pully alright,no leaks or noise,but I'm wondering if the fans on these trucks can make it overheat and if it's worth just putting the old fan onto this waterpump?



Where did the pump come from? Are you sure it's a reverse rotation pump and fan?


99 K3500 RCLB


 
CowboyTrukr 
"10th Year" Silver Supporting Member
Posts: 4543
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
01-12-21 04:44 AM - Post#2811903    
    In response to realroamer

It’s a bit difficult to tell, but the lower portion of the radiator will have scale buildup. You may be able to see it by looking inside the lower hose inlet with a bore scope.

@bowtie44s Jeff, do you happen to have those pics at the ready?

Greg

‘01 Silverado 2500HD 8.1/Allison 1000 Xcab/LB
'00 Explorer XLT 4.0 SOHC V6 Auto
'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500 SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


Edited by CowboyTrukr on 01-12-21 05:09 AM. Reason for edit: No reason given.

 
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2608
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
01-12-21 12:34 PM - Post#2811928    
    In response to 454cid

  • 454cid Said:
  • realroamer Said:
I got a used waterpump and came with a fan,the pump is good,pully alright,no leaks or noise,but I'm wondering if the fans on these trucks can make it overheat and if it's worth just putting the old fan onto this waterpump?



Where did the pump come from? Are you sure it's a reverse rotation pump and fan?





Ah Hah! Was just thinking the same..



 
rockfangd 
"7th Year" Gold Supporting Member
Posts: 3040
rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
01-12-21 03:40 PM - Post#2811941    
    In response to scrambldcj8

I was as well. Bolts on the same but the rotation is reverse which will surely cause issues.
Have to be sure the pump matches perfectly before replacing. Did it seem to happen after replacement?

Old School GM fan FOREVER


Edited by rockfangd on 01-13-21 04:52 PM. Reason for edit: No reason given.

 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-12-21 05:24 PM - Post#2811952    
    In response to 454cid

I pulled it from an exact twin truck with 5.7 ,I'm fairly certain it's the same. I had the problem before I changed the pump. I don't want to be clueless though, how can I be able to test and see if it's a reverse flow?



 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-12-21 05:34 PM - Post#2811953    
    In response to CowboyTrukr

I got desperate and got a bottle of the preston coolant system flush. I hear it's not good for gaskets and seals,but others say it's safe. I lost heat in the cab but the temp was cool and I got enough heat to not fog the windows. The the 4L80E lost all drive,only gave me reverse....cooked,smoking fluid. I pulled it and the clutches were burned together, I replaced everything in the case and rebuilt it. Put it back it's all good now.I then flushed the heater core first,then ran it till I got heat in the cab but when it's in gear it gets close to the red line. I will try running the prestone for a day or 2 then throw a flush tee on the hose and water blast the system. I also replaced it with a new thermostat. I don't kow if I should fight finding bent fins if the flush does nothing or get a new radiator but I will be riding this job to the end,there has to be the fix.



 
rockfangd 
"7th Year" Gold Supporting Member
Posts: 3040
rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
01-12-21 05:51 PM - Post#2811957    
    In response to realroamer

I could be wrong but it sounds like it was not bled properly.
It has to get up to operating temperature to open the thermostat to purge the air. I typically aid in squeezing the radiator hoses to expel the air.
When it gets close to red and you shut it down, is the coolant low after it cools?


Old School GM fan FOREVER


Edited by rockfangd on 01-12-21 05:52 PM. Reason for edit: No reason given.

 
454cid 
Valued Contributor
Posts: 3189

Age: 47
Loc: West Michigan
Reg: 02-18-12
01-13-21 01:50 AM - Post#2811987    
    In response to realroamer

  • realroamer Said:
I pulled it from an exact twin truck with 5.7 ,I'm fairly certain it's the same. I had the problem before I changed the pump. I don't want to be clueless though, how can I be able to test and see if it's a reverse flow?



That should be fine then. It's not actually reverse flow, its reverse rotation. The coolant flows in the same direction but requires spinning in the opposite direction. The change was made with the switch to serpentine belts instead of v-belts.

If the heater core return is plumbed to the radiator, don't use the Flush-T. It essentially only flushes the heater core that way, and not the block. You can flush the radiator with the garden hose in the upper radiator hose, and disconnect the lower hose, after you've run the chemical flush for however long you plan.

I'm not sure if small blocks have block drains.... you might look into that. That would be the best way to flush the block out.


99 K3500 RCLB


 
CowboyTrukr 
"10th Year" Silver Supporting Member
Posts: 4543
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
01-13-21 11:47 AM - Post#2812014    
    In response to 454cid

Small blocks only have the freeze plugs. No specific block drain.

Greg

‘01 Silverado 2500HD 8.1/Allison 1000 Xcab/LB
'00 Explorer XLT 4.0 SOHC V6 Auto
'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500 SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
wagonman100 
Site Ambassador
Posts: 14939

Loc: Baltimore, MD
Reg: 11-27-04
01-13-21 02:58 PM - Post#2812024    
    In response to CowboyTrukr

Small blocks do have a drain plug in the side of the block. It’s a small square headed bolt or on some vehicles there is a knock sensor there on one side. I usually remove them and put a petcock in there to be able to drain coolant low enough to not make a huge mess if I pull the heads. Luckily I’ve never had to use them.

Jay
Friends don’t let friends drive Fords.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier


 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-13-21 04:08 PM - Post#2812025    
    In response to realroamer

I ran the prestone flush through it until it burped up the air. The radiator heater cores must have been plugged from the bottom. I ran the prestone all day and it isn't overheating in gear or idol. I opened the drain plug on the radiator and kept the garden hose in the fill hole and ran the truck till it came clear,drained it all and filled it with antfreeze and even before I burped it again,it ran cool even in gear with all the air still in it. It is burping no problem now. It's running well,stays cool and gets heat inside the cab.



 
rockfangd 
"7th Year" Gold Supporting Member
Posts: 3040
rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
01-13-21 04:54 PM - Post#2812026    
    In response to realroamer

So it is good now?

Old School GM fan FOREVER


 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-13-21 09:45 PM - Post#2812037    
    In response to rockfangd

Seems to be all good. I ran it most of the day got the air out,the rad is staying topped. No overheating driving in the driveway. I will take it for a drive tomorrow and test out my transmission rebuild and see if it shifts right and and won't overheat. Next Job Tranny cooler install I just need to make sure the system runs normal before I run the cooler off the radiator,but not sure if it's better to run the tranny cooler by itself.



 
65_Impala 
Very Senior Member
Posts: 4648

Reg: 12-29-02
01-14-21 08:13 AM - Post#2812053    
    In response to realroamer

  • realroamer Said:
but not sure if it's better to run the tranny cooler by itself.



Yes, it is.



 
rockfangd 
"7th Year" Gold Supporting Member
Posts: 3040
rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
01-14-21 07:01 PM - Post#2812103    
    In response to 65_Impala

That is good. So just air.
The cooler in the radiator serves 2 purposes, It warms the fluid and keeps it maintained at coolant temp.
It is good to have the fluid warmed faster with the coolant as it is less wear, and better performance.

Old School GM fan FOREVER


 
1983G20Van 
Super Senior Member
Posts: 3846

Loc: Bedford, Texas, USA
Reg: 11-13-02
01-16-21 08:00 PM - Post#2812233    
    In response to 65_Impala

  • 65_Impala Said:
  • realroamer Said:
but not sure if it's better to run the tranny cooler by itself.



Yes, it is.



Not in my experience!

When you are really working the converter and trans the fluid exiting the converter can get into the 250-300°F range. The coolant in the cold side of the radiator is substantially cooler than the engine temp and sometimes more than 100°F cooler than the trans temp. Fluid to fluid cooling will remove drastically more heat than fluid to air cooling especially if there are two coolers rather than one.
Best cooling results from plumbing the fluid from the trans outlet to the radiator, then from the radiator into the auxiliary cooler then from the auxiliary cooler back to the trans. My Express van came from the factory with this setup. Kept the plumbing factory just added a larger Trucool auxiliary cooler with the same design. Trans has not gotten over 160°F since. I tow a travel trailer with a 2,800 stall and a 383 making close to 500 hp, so not exactly taking it easy on the 4L85E.


1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 01-16-21 08:03 PM. Reason for edit: No reason given.

 
realroamer 
Newbie
Posts: 11

Reg: 02-11-15
01-17-21 09:41 PM - Post#2812294    
    In response to 1983G20Van

I read that it runs cooler straight to the tranny cooler. I also read the tranny can blow for running to cool and should maintain the temp through the rad. I'm leaning to do it through the rad. Who has run their 4L80E straight to the cooler for years, and why does it help your tranny that way?



 
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

566 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.072 seconds.   Total Queries: 17   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 08:29 AM
Top