best radiator for turbo 3b (1 Viewer)
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Was it 3 core or 4 core when recored if it was 4 cored it should stay ccol and may be the TStat
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RufusTheDufus
SILVER Star
There's a company in southern CA that will do a custom 4 core for you. I forget the name but can look it up if you're interested.
I recently had my HJ45 radiator re-cored locally. (It's a 4 core.) They were able to add two rows of extra tubes on each end of the radiator for a total of 16 more tubes. The shop I took it to works with an outfit that builds their own custom copper/brass radiator cores. They can build just about anything that will if your end tanks.
I recently had my HJ45 radiator re-cored locally. (It's a 4 core.) They were able to add two rows of extra tubes on each end of the radiator for a total of 16 more tubes. The shop I took it to works with an outfit that builds their own custom copper/brass radiator cores. They can build just about anything that will if your end tanks.
1100 after or before the turbo?
cruiser_guy
Out of Africa / North Africa
I run a factory 4 core rad. with A/C and my EGT's can climb to 1250 pre-turbo and generally the truck is just fine. In the middle of summer pulling a hill in Arizona at 115 F outside the temps climb and I need to kill the A/C for the hill climb only.
x3 on a 4 core.
Stock rad is 3 core
The problem is caused by not enough water getting by the thermostat. I had the same problem with my 3B, went through 2 radiators, 3 core, 4 core, water pump, new hoses, new fan clutch, 3 thermostats, nothing changed the problem, put enough load over a period of time and the motor would creep up in temperature, oh yes turbo set at 11psi, EGT pre turbo never ran above 1200F, I finally hooked up an electronic thermometer to the out put of the thermo housing and to the input to the water pump, I found the radiator was giving a very good temp drop so I figured the thermostat was not allowing enough water out. I drilled and tap a port into the lower thermostat housing and made a tee out of copper for the upper hose and installed a vacuum controlled valve from a cadillac to control the water flow. I had a manual valve to turn it off and on. When the engine would start to run warm on a hard pull I turned on the vacuum valve and the temp would go right down. I went so far as I took a thermostat and wedged the thermostat open used a dremel and ground out the opening, it allowed more water to flow when open which helped.
I have included some pics.
Jim
I have included some pics.
Jim
- Thread starter
- #10
interesting fix. i guess i could remove the thermostat and go up a hill that would normaly heat the truck up if it stays cool then the rad is fine and i need to work on the thermostat. are there any aftermarket thermostats that flow better. thanks
cruiser_guy
Out of Africa / North Africa
Non-A/C is 3 core, A/C equipped trucks have a 4 core as stock.
If you can look through the rad filler you'll be able to count cores. Otherwise I think if the core takes up the entire tank area then it's a 4 core. If there is space at the back then it'll be a 3 core.
on my bj70 i have a 4 core bj74 rad and 82c tstat and I run cool as can be now.
pyro readings post turbo
600 or less normal driving
700 on the highway
800 at high elevation and long climbs. I can't get it past 800 now.
water temp is usually 190. I see less when going down big hills and rarely does it get to 200 unless i'm really pushing it.
I run 15psi max. usually i'm pushing that on the hills and on the flats maybe 12psi.
going to the 4 core and toyota red coolant made the biggest difference.
pyro readings post turbo
600 or less normal driving
700 on the highway
800 at high elevation and long climbs. I can't get it past 800 now.
water temp is usually 190. I see less when going down big hills and rarely does it get to 200 unless i'm really pushing it.
I run 15psi max. usually i'm pushing that on the hills and on the flats maybe 12psi.
going to the 4 core and toyota red coolant made the biggest difference.
I have never seen an aftermarket thermostat that fits the 3B housing that has the second valve on it to bypass the radiator and run the coolant straight back into the engine at low temperatures.
I had an aftermarket t-stat in my BJ40 (3B engine) once, it ran a little warmer than the stock t-stat on hard pulls and dropped the temperature right off the bottom of the guage on long slow descents.
If you run with no t-stat some of your coolant will recycle through the engine without ever going through the radiator. This may affect the results of your experiment.
iirc it's an 82c (180) or 88c (190) .. really not that much of a difference IMHO
It's a stock item
It's a stock item
RufusTheDufus
SILVER Star
You should be able to count the copper tubes viewing the front or rear of the radiator. Look at the junction of where the core tubes are soldered to the end tanks. The fins typically aren't in the way at that location. You should see columns of brass tubes going into the end tanks. If a column has 3 tubes it's a 3 core. 4 tubes, etc.
Taking the thermostat out won't work, the factory thermostat has a round disc at the bottom, as the thermostat opens it blocks the radiator bypass which makes all the warm water from the engine go to the radiator, one way to prove the thermostat water flow theory is drill 3 or 4 holes in the main body to let more water flow thru, it will ruin the themostat but it will prove the theory. NAPA sells an aftermarket thermostat, I bought one and it made my problem worse when compared to the Toyota one the brace over the top of the thermostat was 4 or 5 times wider which makes the opening of the tstat smaller it was this discovery that started my test, I pushed the tstat open with my finger wedged it open with a small nut under the push rod and used a dremel to grind the opening as wide as possible this solved my problem. I did not trust the tstat so I built the bypass with valve it works great using a factory Toyota tstat.
One other thing, a common way to cool of an engine is turn on the heaters, on my 3B 1985 BJ70 the rear seat heater water hose comes off the lower tstat housing which would work to cool off the engine, the front heater comes off the back of the head if you turned on the front heater it would make the engine run hotter as the heater bypasses the head and retuns the water to the water pump. Look at how your hoses are routed to see where the heater picks up its water you want it after the head not before.
