Coolant system knocking upper rad hose pulses

[chrismcdaniel1]

Guys - thank you in advance for any and all assistance. I am new the forum so please excuse me if this was posted before - I attempted a search but found nothing.

The cooling system in my 93 4wd ranger (4.0L AUTO TRANS) begins to pulse/knock/click when the vehicle reaches operating temp. The water pump was recently replaced as well as the TSTAT. New gaskets on both. Complete burp of the system and fill was performed as well (heat on FULL BLAST engine at idle)

I replaced the TSTAT again last night and the click/knocking has stopped, but the pulsing is still present. You can feel it in the upper hose from the TSTAT to the RAD. The upper hose is soft and the lower hose feels tighter. Another point is that with the radcap off the coolant level maintains until the pulse the it drops and recovers. Is this normal? Guess I am used to seeing the coolant "flow" through the RAD.

My mechanical crew is stumped (Sunday garage mechs ) as none of us have experienced this before. I did read there is a TSB on a similar issue which requires a coolant By-pass kit (Part # F8PZ-8522-AA) installed, but the part is UNAVAILABLE.

Has anyone experienced this before? The heat blows HOT and I cant find a loss of coolant anywhere.

 

[shovelmike]

It sounds like you still have an air bubble in the system, it can be hard to bleed it all out. That top hose is the high point in the system, try again burping it out there.

 

[naford]

If you think it is air. Park on a hill with the front of the truck higher than the rear make sure it is warmed up.

 

[chrismcdaniel1]

Guys thanks for the tips. I have a slanted driveway so after trying to burp the system on flat ground for 45min I attempted it on the driveway.

Basically what I am seeing is this - with the cap off the coolant in the RAD will go down, then rise, then shoot like a geyser. the lower hose is much cooler than the upper hose. When the fluid level dropped and stayed there I filled it. The overflow was full.

With the cap on, and before the pulsing starts, the upper hose has significant pressure. then the TSTAT opens (or pulses) the hose losses the pressure. The lower hose still stays cooler.

Any additional help is appreciated

 

[chrismcdaniel1]

Does anyone know if there is an air bleeder valve on this engine? I keep reading that "most" vehicles have one...

 

[Tranger994x4]

Does anyone know if there is an air bleeder valve on this engine? I keep reading that "most" vehicles have one...

I know this thread is 10 years old but did you every find the solution to this problem? Im having it myself.

 

[bennyHanna]

This problem has just risen for me

 

[SenorNoob]

Every time I've seen this it's either lots of air, or a clogged heater core.

 

[bennyHanna]

How would I get rid of the air, I just changed timing cover gasket, pulled the radiator off and everything, just put a new heater core in it, thought it would fix it

 

[SenorNoob]

Park on a steep hill facing up or put the front on ramps/ jack it up. Fill the system cold. Hold one hand over where the radiator cap goes and milk the upper radiator hose. After a few strokes the level will be noticeably lower. Refill it. Repeat until the level doesn't go down anymore. Then put the cap back on it, fill the expansion reservoir to about halfway between the full mark and the actual top of the reservoir. Remove jack/ramps as necessary. Then go for a short drive. You want to get it up to operating temperature. Come back and park it. Don't touch anything again until it's completely cool. Several hours. I leave mine till the next day. You should notice the level in the expansion reservoir is lower now. Refill it to the full line and you should be ready to go.

 

[bennyHanna]

Ive tried the squeezing of the hose thing, also the upper radiator hose flattens pretty bad,

 

[SenorNoob]

Bad hose? I know some of them have that spring inside... Maybe you need that?

 

[4.0blue98]

Mine may have been a coincidence, but I chased the thumping cooling system for a few years. Only did it when it was below 40F or so. Mine wasn't terrible but just annoying. A few months back I changed the water pump that was starting to leak out the weep hole. Haven't had any noise since. Used a Gates WP but pretty sure the previous one was a Gates too.

Like I said, could have been a coincidence.

 

[bennyHanna]

Thank you guys dearly, y'all are an asset to this website and a blessing to this world

 

[superj]

I would geuss that is a water pump issue