4d55t Running Temps

[Zaque]

Hello the radiator on my 84 ram 50 TBD keeps sending fluid to the over-flow and my temp guage doesn't work right. Im wondering if it is actualIy overheating or not. I replaced the thermostat, waterpump, and radiator cap but it is still doing it. I measured the motor with a temp gun after a 10 mile trip and it says it was running at 220 measured at the side of the block. Is this normal? What could be wrong? Oil is good as well as antifreeze.

[royster]

Hey Zaque~

Radiator flush is my guess, but I'm not real familiar with 1st gens. However, that would be the next blockage. Also, the temp sending sensor might be dead or dying.

[geezer101]

They are designed to push coolant out of the overflow pipe as the coolant needs somewhere to escape to when it expands from heat. Are you getting coolant return after the engine cools off? If not then the diaphragm in the overflow bottle is probably split or perished. And what do you mean the temp gauge isn't working right? What symptoms is it showing?

[Zaque]

About 10 minutes after starting the truck just idling the guage will jump up past the red line on the guage but the motor only measures 140. The motor doesn't run like it's overheating but it does measures around 220 or 230 after longer trips.

[geezer101]

Sounds like an electrical gremlin if its redlining the factory temp gauge after starting up (I'm assuming you have an auxiliary aftermarket temp gauge in your truck) . I would recommend a complete cooling system clean out if you have no idea when or if it has ever been done - and making sure you're running the correct coolant.

[Zaque]

Flushed the radiator with no luck and yes it is the stock guage. Is 220 a normal temp for those engines?

[camoit]

A real gage to check the temp is needed. Manual or eletc. But not the stock one. Or one of them inferred ones then just shoot the t stat housing.

[geezer101]

After a quick McGoogle I found that the average normal operating temperature for an engine should be 205 - 212 f so if you are consistently running hotter either your radiator is on it's knees or your thermostat needs to be swapped for one that opens at a lower temperature.

[geezer101]

*that should be a diesel engine

[Zaque]

Have been checking it with the infrared gun. Would a bad air cleaner cause hotter temperature. I just ordered a new air cleaner because you couldn't even see light through the old one.

[geezer101]

Have been checking it with the infrared gun. Would a bad air cleaner cause hotter temperature. I just ordered a new air cleaner because you couldn't even see light through the old one.

A completely clogged air cleaner shouldn't be the cause of excessive engine temps but weirder things have happened. I was thinking that using a temperature gun on the block isn't indicative of actual operating temps either. Best place to get an accurate reading off the engine is from the outlet on the inlet manifold to the radiator as this will be the last point the coolant leaves the engine (which is both logical and obvious as this is where you'd find a temperature sender unit anyway...)

[Zaque]

I checked at the thermostat housing and the turbo as well as the block and temp sending unit to compare temps. Temp/glow unit is on top of engine near glow plugs.

[mikewarme]

You will never be able to "flush the radiator" correctly. Take it to a radiator shop for $70 they remove the upper and lower tanks and put the core in a hot bath and clean the tubes out. More than likely you have set-up for a cracked head. None of mine overflow out of the bottle. It is normal for just a little to go back and forth but not enough to boil out of the canister. The gages on these things are bullet proof. Replace the temp sensor located on the front left side of the head next to glow plugs or check the harness connecting to it (Part of the injection pump harness). Now if you have a rusty truck I might believe you the gage is done but otherwise they last forever. Let me know if you need help as I have parts to share if needed. The pointer should never go more the 1/4 way up on these. Mine always runs about 210. 230 is very hot. The death of these motors is heat so fix it before driving more. Hint if you want to try a new radiator just find one for a 4x4 2.6 as they are the same size just have the cooler for the auto trans. MB221988, MB222043 were factory part numbers. Start googling to find the aftermarket replacement Hard to find but they exist. Basically the stock radiator worked perfect when clean. Just a little plugging up and they over heated. Radiator pros makes a good radiator with better cooling.

Mike