chronic overheating

[svoking]

I have an 86 ranger that came with the 4D55 and I hop you guy's can help.
First is the 4D55 a revers flow cooling system?
Before I got it running I built a new radiator 19x20x2 it's a duel pass cross flow.I put 8,000 miles on it after and then developed an over heating problem. It will get up around 240* in about 2 miles top hose is hot bottom is only warm. I have tried 3 thermostats of two different brands, a brand new water pump and got no were. Then discovered a blown head gasket and rebuilt the hole engine(it was shot any way) and it dose the exact same thing. I don't know what to do, any and I mean any idea is appreciated.

[camoit]

It sounds like you have an air lock somewhere. You need to ensure that the engine is actually full with water. Some times you need to take the thermostat and drill a small 1/8 inch hole in the flat area to allow air to escape through it. Can you post some good pictures of what you have. we would like to see if there are any high spots that may trap air in the block.

[svoking]

I'll work on pics. the t-stat has three bled holes. is it a revers flow system?

[camoit]

shouldn't be as far as I know. I have never seen one where the lower rad hose is the out flow. You did put the thermostat in so the sensor was down, right?? On the water pump does it have a replaceable base plate. I know on some Toyota engine the pump and base plate are separate. If the base plate is warn they won't pump enough water.

[svoking]

don't think so, the spring side is in the pump hosing. is that wrong? I have no kind of service manual for it.

[camoit]

Ill come up with a manual ASAP Give me an hour.

[camoit]

OK look in the manual section. I just loaded a crap load of manuals in my server. You will find the 4D55 in there. There is like 5 manuals of just the 4D55. Along with a boat load of others. I will be moving them around and organizing them soon.

[wrngwae]

i believe it is. the thermostat is on the actual water pump housing.aka bottom hose. but it sounds like a different issue perhaps the radiator has gotten plugged???? or check the correct direction of the thermostat.... the spring should face towards the pump its self..... otherwise the spring dosent get any heat and open.

[PowerRam348]

i agree, the thermostat might be put in wrong. you wouldn't be the first guy to do that, i've done it myself. i would also check the flow through your radiator to ensure that it isn't plugged or partially blocked.

[svoking]

I described the orientation of the thermostat all ready. I'm more concerned that the radiator may be over taxing that little turd of a water pump.

[Fordubishi]

there's your problem right there, Aftermarket 1200 cfm electric fan. the stock fan will pull between 1800-2200 cfm. the cheap aftermarket fans are really just for added cooling. I've run into this a number of times and I put the stock fan back on or go with a new 2000+ cfm fan and the problem usually goes away. The fan I'm using is a 14" 2100 cfm Derale CFM pusher http://inet.derale.com/ClientImages/10_3_High%20Output%20Single%20RAD%20Fans.jpg, and it keeps a 302 cool (180-190 degrees) with the fan temp sensor set at around 160-170 degrees.The basic idea for an aftermarket electric fan is to cover 75% or more of the rad,a shroud should cover the rest that the fan doesn't.Quick way to make a shroud is take some card board and fill the sides beside the angle iron and top and bottom where the fan doesn't cover the rad, take it for a quick run and see what happens. also check the CFM spec's of that fan. 950-1200CFM is standered for a 16" cheap aftermarket electric.

[PowerRam348]

yes, i agree, you need a bigger fan. i have two on my radiator, one sucking air thru on one side and one pushing air thru on the other side. i have mine set up on two thermostats; one set for 170 degrees and the other for 190.

[miked50]

i've downloaded a 4d56 (91-93 & 94 & subsequent) manual from a site (russian i think)....i forgot the exact web address. i'll search my documents.......mods, is it ok to post the website of the manual in this thread?

[miked50]

i'm also experiencing overheating before. previous owner removed the t-stat. i put in a 82C t-stat. overheating gone. but then after a few months, temp rises esp. on bumper-to-bumper traffic and WOTs on highways. what i do is release the hood lock on traffic. it's effective. on highway runs, i just let off the throttle and maintain my speed at about 45 mph to cool it down. maybe i need hood louvers.

[camoit]

We have a full set of manuals in English in the new batch of manuals I found. Over 216 of them. The diesel comes in 1 zip file and covers all of them or so I think.
Did you go back to the stock fan and shroud?

[svoking]

No need for a fan at all so far, still kind of testing it. But 500 miles never been over 200* never turned on the fan.

[camoit]

If you want some louvers you should be able to find them at Pep Boys unless you want real nice trick ones. I'm going to be getting some made from a Camaro to put on my hood soon. My fiberglass guy is going to be making some for me in the near future. You can see what they will look like in my build thread.

[svoking]

an update it was the stant thermostat that was the problem. installed a miladon high flow 160* and i have yet to turn on the fan or see temps over 180*

[mazda diesel]

My 4d55 which is from a Mighty Max has the lower hose as the outlet, which is different, I would recommend checking the thermostats, I had the exact same problem and I used a non contact thermometer and figured out that it was the thermostat, even though I put a brand new one in just the day before, lesson learned, test them before you put them in... i finally found one that opened when it was supposed to and I have had no problems since.
Seth