Bleeding Radiator on my 2000 Ranger

[Elizabeth Walter]

How can I bleed the radiator? I have replaced the water pump, thermostat , hoses and had the system flushed and still have an overheating problem. Any suggestions would be greatly appreciated.

 

[Tech By Trade]

What I do is pop the thermostat housing and fill the block to the top through there, then put the thermostat housing back on and fill the rad to the top. No bubbles that way unless there are a few back in the heater core, but they will usually work their way through.

 

[XLTrunner]

Or...elevate the front end, remove the radiator cap (engine cold) and start the engine. Let it run until it warms up (approx. 10-15 mins) while having the heater and blower on High. If you have trapped air, you'll see it bubble out the top of the radiator. Put the cap back on, drive it around a little and recheck coolant level inside radiator once it cools down again. Add if necessary. I do this every time I change coolant, radiator, water pump, thermostat, etc. and have never had an overheat problem. Good luck!

 

[J_C]

Make sure your fan is cycling on.

 

[koda2000]

What I do is place the jug of 50/50 antifreeze mix higher up than the engine (cowl or even roof) then I use a small plastic hose to siphon the antifreeze into the radiator slowly. Takes a little while, but I've never had a trapped air problem when doing it this way. I have had problems when just dumping the antifreeze into the radiator quickly. Wish Ford and put a bleeder valve high on the engine (the way other manufacturers do). I've also heard of opening the thermostat and holding it open with a aspirin, but never tried this method.

 

[lobo411]

If the OP had the rad flushed, doesn't that imply that it was done at a shop? If so and there's a major air bubble trapped, then the shop should deal with it.

I've never had enough air trapped to cause an overheating problem, though, and I don't do anything special to purge air from the system. All I do is refill the system, run the engine with the radiator cap off for a bit and add coolant as the air gurgles up, and then check the coolant level in the radiator after every heating/cooling cycle for a few days.

I'm betting that the OP has some other problem causing the overheating. Maybe the OP had the water pump and hoses replaced and the system flushed to try to fix this problem, but those turned out not to be the real problem.

 

[J_C]

One trick I have read to auto-bleed is drill a little hole in the perimeter of the thermostat, just inside where the gasket sits, if it doesn't have a bleed valve built in. However, and it's dependent on the size of the hole(s), this can make the engine take longer to get up to optimal operating temperature, including heater output temperature.

I assume the radiator isn't clogged, though you should be able to shine a flashlight down in, and gauge the rest of the radiator by what you see there, but you might need to siphon off some coolant to get a good look.

 

[koda2000]

The 4.0L SOHC is notorious for trapping air in the cooling system/engine.

 

[J_C]

^ There's something we weren't told, whether it's the 2.5L I4 or 4.0L V6 engine. Not sure but that year might've also had a 3.0L V6.

Wait, after further research, the following site suggests that Ranger wasn't switched over to the SOHC 4L (from OHV 4L) until 2001:
http://www.therangerstation.com/tech_library/4_0_Page.shtml

 

[RandomNerd2000]

I've heard of using Asprin and wedging the T-Stat, also heard of getting a T-Stat with breather holes in it. What I normally do it just let it run without the cap on it and get to temp and run at temp a few minutes and just make sure it's full, the 4.0 wasn't happy with that method though, what I did with my 4.0 is just fill the block and lower housing, installed the thermostat and upper housing, filled the radiator and overflow, let it get to temp, cool down, filled it up again, go to temp, cool down, fill up (with heat on OFC) until it quit taking coolant, then filled the overflow. The 01 I have didn't have heat up until September when it was colder and raining, and I heard a burp in the dash and had heat, dropped a good bit of coolant too, but that comes from everybody stalling the thermostat housing for years.