Possible Cooling Problems

[titanmax]

Need help with possible overheating issue.

I have been dealing with a cooling problem in which my temp gauge seems to read that the coolant is rising and overheating during extended periods of operation, i.e. over 15 minutes of driving.

At first because the gauge seemed to read a spike in temp and then it would drop I parked the truck on a hill and took the cap off and ran the truck for like 30 minutes or so to make sure there weren't any air pockets. gauge stable whole time.

The top hose the returns coolant to radiator heats up and gets hot when I was checking for air pockets also.

Even after this I had the same problem so I proceeded to replace the temp sending unit itself. Problem still there.

I thought it might be a head gasket that was leaking but there was no white smoke from burning coolant, there was also no coolant that appeared to be in the oil and a block test I did just came back negative.

There are no visible leaks and Im thinking that my next course of action will be to put on a new external water temp sensor at the return hose to monitor the actual temperature.

Thanks,
Max

93 Ranger 4.0

 

[daniel3507]

Have the radiator cap and thermostat been replaced? Start simple and replace those. Might get lucky with them.

 

[titanmax]

Okay, so I replaced the radiator cap and put in an aftermarket temp sensor. Fluctuations still present. The temperature seems to fluctuate between 205 to 220. Even though this seems to be within the normal, although higher side of the operating range, the range of fluctuation and speed (within about 30 seconds) seems abnormal. Temp gauge, heater core, TStat, water pump and radiator have all been done within the last 3 years. There are no visible leaks but I'm going to crawl around and check tomorrow morning. Ideas, I ran the truck for like an hour parked facing up a hill with the cap off to make sure the system was cleared of air.

Any ideas appreciated.

Thanks again,
Max

 

[holyford86]

I've seen bad thermostats out of the box, for the price, its worth a try.

 

[shane96ranger]

A couple of random thoughts I had:

Is your thermostat clocked correctly? Meaning, is the pellet at the top (where the air will go)? It is very difficult to properly bleed air out if it isn't in the right spot.

Is your fan clutch in good working order? Check to see if the viscous fluid is leaking. You can usually see wetness/oil on the shaft if so.

 

[titanmax]

Tstat problems

Fan Clutch seems good, no leaking and runs smooth.

I was dropping in a new Tstat today and was able to get one of those rubber gaskets so that I didn't have to use RTV sealant. I was able to get the right side and the bottom side bolt in fine with no problems. Put the left side top bolt in and hand tightened it down to snug, with seemingly no problems.

Went to tighten it down to final tightness of 10ft/lbs and the bolt just kept spinning on me without tightening down. Pulled the bolt and it had little pieces of the thread from the bolt hole in it. Not good.

Looking for advice on what to do. Is there any sealant I can put on the bolt hole to get it torqued down at least a little. Or will maybe RTV plus the rubber gasket keep this thing from leaking without being able to fully tightened it down.

Not sure how this happened, I'm meticulous with bolt placement and fit and in this case I hand tightened it and it went all the way into the whole easily. The last person to do this Tstat two years ago was a local shop though...hmmm.

Thanks,
Max

 

[pcollins]

Is it an easy hole to get to? If so i'd go with a helicoil. Take the housing etc off...stuff a rag in the channel where the coolant goes and drill/tap put the helicoil in. They don't take long at all to install.

 

[titanmax]

Buttoned everything back up and have driven it a few times and thankfully no leaks from the thermostat housing. However, the engine seems to run cooler initially, right around 200-205 but then after 10 minutes or so of driving, the temp will jump up around 215-220 or so.

Going back to the fan question. I have been trying to see if the clutch is engaging the fan at all. After the engine gets hot and then I shut it off, the fan will keep spinning with the engine off for like 15 -20 seconds. Is there any other ways to test if the fan clutch is engaging properly. I have heard that a properly working fan clutch shouldn't allow the fan to spin more than like two or three times around once the truck is shut off.

Thanks again,
Max