Weird Rumble/Vibration in 94 Sidekick and cooling issues...

[TH3_#1_tracker_fan]

Ok so here's the deal. Anywhere from around 35mph and up there is a vibration/rumbling sound coming from what *SEEMS* to be the rear end of my 94 Sidekick. It doesn't happen when I'm floating the throttle (just enough to keep going), only when accelerating and especially when decelerating. It's not bad enough to where it can't be driven... In fact, I drive it every day. It's not U-Joints because they were literally just replaced. There is no looseness at the splines or either of the U-joints of the driveshaft. It's a 2WD. I'm thinking maybe clearence issues in the diff. or perhaps the pinion bearing..? Another issue I seem to be having is as long as I keep around 55-60 MPH, it stays nice and cool. However, anywhere above that and it starts heating up. I've put two thermostats in it, so I know that's not the problem. Partially clogged radiator..? Also, my 95 Geo Tracker is doing something very similar to that. I actually removed the thermostat from that and it still heats up. Normal at those particular speeds, but anywhere above and it heats up. It in particular just kind of starting doing this all of the sudden. I replaced the water pump this past winter in the Tracker. Both have a good heater, so that eliminates a stopped up heater core. I believe it too may have a partially plugged radiator or a blown head gasket... Speaking of which, I just replaced the head gasket on the Sidekick, so that kind of eliminates that, but I kind of assume that whatever blew the first head gasket probably has something to do with why it's heating up now (i bought it with a blown head gasket). Lemme know what you think.

[Richard Craneum]

Is it automatic?

A bad Torque Converter?

I was thinking on a bent drive shaft or out of balance, but that would not cause to overheat.

But that is a SWAG on my part.

[TH3_#1_tracker_fan]

Lol I forgot to mention that it's a 5 speed. And I would think if it were a bent shaft, it would do it all the time, reguardless of weather if has a load on it or not. I might also mention that my Tracker is also kind of starting to do it under decel and is also a 5 sp 2wd.

Edit: U-joints are good on Tracker too.

Edit:Edit: I know this is kind of stupid for stating, but I don't think the two probs are related lol.

[jtgh]

two cars, 1 post, ouch. this will be fun,.
and multiple , issues. sure.

car one , has clogged rad, or it is stuck in limp home. if car has full mpg and power then its clogged rad, or slipping belt (some slip quietyly dont you know)

the heater core does not cool the motor ( the damper blocks it in summer and it does not help cool the motor in the summer)
the core is always on and flowing 100% but air is not.

but what makes you think its over heating?, not that useless dash guage , huh?
IR gun the stat housing and dont guess. find out the truth, then fix it if it really is a problem, , no boiling over, no fuild pushing out overflow tank , no exhaust gasses in the top of rad filler area. look for all the signs (besides the gage) and then IR gun it.


id post these seperate.

the noise issue will take hands on expert to find or racking it up and running in a rack bay a pro with a stethoscope.

inspect the rear brake shoes for impending axle bearing fail ,or current fail.


over heating is a complex issues

have you checked to see if the ignition time is exact.
if not the cam belt has slipped.

did he replace belt and idler, if not idler seized (ing)

did you retorque head after a few k.
did you set lash correct.

how is compression, id check that 1st time any motor acts funny.


air on top of motor can be an issue. burb motor, STAT air bleed forward?
air on top of motor will may guage rise and fall , randomly.


over-heating-why?


PS: clue ,never make assumptions while working on a car.

it will lead you to a full expensive circle of pain, money and labor.


defective new parts ( or worse ones made in china.) or bad luck. happens all the time.
bad install
bad adjustments.

compression test
then
vacuum test

Ir Gun it.

$12 tool at harbor frieght and worth $100 , not counting the tail chase issue and the cost of that.

[jtgh]

http://www.kick-fix.com/Cooling-engi...t-housing2.jpg


rubber meets road. 170F good.

you can find the bad tubes too , so easy its childs play today.