so some stupid questions i want answers to

[brdhntr]

ok. this is not a jeep specific question rather an all makes question. here's the deal. i know quite abit about vehicles and concider myself a pretty good mechanic. with that said, i think i know very well what the answers to these questions are but a mechanic is trying to convince me sifferntly(trying to get more money). so i will not say what i think i know, i will ask you to tell me. please let me know what you think. (i should let you know i took it in to be fixed cause it's to frickin cold out to fix it myself since the jeep and the audi occupy the garage).

 

here we go:

 

a pressure test of the cooling system testing for leaks, pressure, and radiator cap pressure- the test should tell you of any leaks and if the radiator cap is good. the test will not tell if there is a head gasket leak.

 

a water pump gets weak and does not function properly over time even though it is circulating coolant.

 

an addapter attached to the radiator cap location (looks like a radiator cap with a funnel in the middle) can tell the cooling system is flowing properly. when the coolant goes up in the funnel, then goes down(engine at operating temperature), there is a problem with the cooling system. the coolant flow and level should always remain the

same when the engine is runnnig.

 

a temp gauge that goes up and down while driving is a sign of a bad thermostat.

 

so let meknow what you think. pleez!!! :D

[mule13]

with a cooling system pressure tester you can test for a cracked head or blown head gasket if its blown in the cooling side.to do so remove the radiator cap install the pressure tester but don't pump it up. crank the vehicle and watch the pressure gauge if it builds up over system pressure its probably a blown head or gasket. leats thats how we checked on the diesel engines back in the day :)

 

idk about the water pump seems either it pumps water or it doesnt, i guess over time it would wear a little but it should still provide adequate water flow to the engine.

 

as i drive down the road my temperature gauge goes from 190 to 210 back and forth as the thermostat opens.if you have an accurate gauge it seems you would see this maybe with a less sensitive gauge you wouldnt not sure. but if you have a good gauge how would you not see this?( i guess it could depend where your temp sender is located too)

[flint54]

RE: "a water pump gets weak and does not function properly over time even though it is circulating coolant."

 

I have seen several water pumps with eroded impeller blades. Yes, they will still move water to a degree,

but may no longer move the volume/rate to provide the necessary thermal exchange. On a ~20 year (or

more) year old vehicle, it's pretty cheap insurance (and easy) to just replace the pump if at all suspect.

 

A fluctuating temperature gauge could be several things, including a faulty gauge, a poor ground, a faulty

sending unit, intermittent coolant flow, and probably several others that don't immediately come to mind.

My first suspicion would not be the thermostat.

 

 

Tom

[dasbulliwagen]

Coolant level does change, thats why there is a full cold mark on your coolant resevior, it allows room for expansion of the coolant. The level should be higher when hot, and lower when cold.

 

And a pressure tester telling weather or not a head gasket is bad.... it can happen several ways. I saw just a month or so ago, the tech that works next to me was pressure testing a ram pickup, but saw no coolant leaking as pressure dropped. So he was stumped, and was going to pull it putside, but when he hit the starter, the engine hydrolocked because one of the cylinders was full of coolant. But I guess that all depends on how bad the head gasket leak really is. it could also leak coolant into the crankcase, in which case youd get milky inneffective motor oil, or leak coolant into the transmission cooler line inside the radiator, and make your trans fluid milky and inneffective. There are many variables to this.

 

The temp guage fluctuation too me would mean a bad thermostat, because every one Ive ever seen would get to its mid point and stay there with little to no noticable movement, but ive not had any Jeeps with a guage like that, so that experience comes from other vehicles.

 

As for the water pump... horribly worn impeller blades are fairly rare, the pump will usually leak long before the blades get that worn out. Ive only seen it a couple times myself over the years, and again, not in a Jeep.

 

Good luck and let us know what you figure out.

[brdhntr]

ok. so no one was specific about the coolant level, or for what i'm looking at. should the coolant level fluctuate WHILE the engine is at operating temp and running, say going up and down in the "test tool" that was used (coolant going higher and lower in the "funnel")?

 

would the fluctuation happen due to no pressure in the cooling system due to the lack of the radiator cap?

 

also, could this fluctuation be caused by a bad thermostat?

 

this is an important question for what is going on. i'll explain whne i get a few more opinions. i don't want to influence any of the opinions/answers.

 

please chime in. it doesn't matter how experienced you are or if you know, give your thoughts. :help:

[mnkyboy]

Their test tool is for filling/bleeding cooling systems without spilling,any tool truck sells them.

 

I don't worry about the coolant fluctuating as long as its not blowing bubbles or trying to push the coolant out with the cap off.