Temp gauge fluxuation/Coolant Thump

[1993Saturn]

I have the common problem of the temperature gauge moving up and down and occasional coolant thumping felt on the passenger side. I know the OEM gauge sensor is working correctly, because it directly matches the heat output of the heater. The first time I heard the thumping, it about scared me out of my gourd!

Anyway, this link told of the TSB for the problem:

http://www.explorerforum.com/forums/showthread.php?t=64493&highlight=thump+in+hoses
The 2 TSBs address both problems separately.My '94 is supposed to have the water pump replaced with the Ford upgrade. The '95 gets the bypass kit installed for the thumping, which mine needs as well.

Now, I have flushed the system, replaced the pump, thermostat, both coolant sensor and senders. Vacuum gate works for heater core. What about the Bypass kit? No pictures can be found. What can be rigged up to copy the setup? Does anyone have pictures/instructions for it?

 

[1993Saturn]

Chilly in the High Desert

OK, I have a way of scaring people away with my posted questions lately. A week ago, I posted 3 separate issues and zilch on all of them. 57 have looked at this one. I need someone that knows about the results of the bypass kit or another work-around for this inherant problem. It's freezing out and I don't get very much cabin heat.
Hope someone knows something.

 

[cogs]

did you burp the system?
http://www.explorerforum.com/forums/archive/index.php/t-272433.html

From the service manual:

Fill the cooling system with a 50/50 ethylene glycol and water mixture. Allow several minutes for trapped air to escape (bubble out) and for coolant mixture to flow through the radiator.

Install radiator cap to pressure relief position by installing radiator cap to fully installed position and then backing off to first stop. This will allow any air to escape, and minimize spillage.

Slide heater temperature and mode selection levers to maximum heat position.

Start engine and run at fast idle (approximately 2000 rpm) for three to four minutes. Shut engine off.

With engine off, wrap radiator cap with a thick cloth, carefully remove radiator cap and add coolant to bring coolant level up to filler neck seat.

Replace radiator cap to fully installed position. Then, back off to first stop. Operate engine at fast idle until the upper radiator hose (8260) is warm (water thermostat (8575) opens). To check radiator, shut engine off, wrap radiator cap with thick cloth and carefully remove radiator cap. Add coolant if necessary. Replace radiator cap to fully installed position.

Open the small cap on the top of the radiator coolant recovery reservoir. The large cap is for the windshield washer reservoir. NEVER put coolant mixture in windshield washer bottle.

Using a suitable suction gun, remove all coolant from radiator coolant recovery reservoir.

Add 1 liter (1.1 quarts) of 50/50 mixture of ethylene glycol and water to the radiator coolant recovery reservoir. Close the small cap.

 

[1993Saturn]

I have done that and I still get a fluxuating gauge. It corresponds with the heat output. You can actually see the gauge needle move.
That is why I asked about the bypass kit. It was a big enough problem with the 2nd gen for Ford to create it. My '94 is a transition vehicle so some of it is '95 stuff.

 

[ernzo]

i had this....i burped the system using the techniques outlined here....explorer on incline etc....it did not really help imidiately.....i changed the cap and thermostat....(prior to burping...)....nada.....what I think happened was the water pump i installed when this all started happening was somehow jacked up or incorrect and....anyway.....after like 6 months the air 'finally' left the system and things are stable....i will say that burping can be difficult and it is hard to know of anything is really happening.....i will changed the WP again when the weather get warm.....this time to a good one...

 

[Nedwreck]

I have a '92 and a '93... any time I have to deal with the coolant system, I fill and run the engine a bit, filling as I can.

Make it a point to keep the overflow filled to full. As you have heating/cooling cycles, it ~should~ continue to expel air as it heats, and draw fluid back in when it cools.

Air trapped in the heater core can be a real bugger if you don't have good flow thru the core. I'd suggest backflushing the heater core. This would seem to correspond to the TSB you linked to, in that slow coolant flow seems to be the issue regarding steam pockets in the core.

Another "fix" to air pockets trapped by the thermostat itself, is to drill a 1/8" hole near the edge of the stat (not in the sealing ring), and install it with the hole at the top... if your t-stat doesn't have this hole already. Two holes won't hurt either really. (this is an old Mercedes trick)

Sorry, I don't have any info on the bypass kit.

HTH

 

[kkjb4x4.0]

Does your gauge fluctuate with the heat turned off?

 

[Roadrunner777]

OK, I have a way of scaring people away with my posted questions lately. A week ago, I posted 3 separate issues and zilch on all of them. 57 have looked at this one. I need someone that knows about the results of the bypass kit or another work-around for this inherant problem. It's freezing out and I don't get very much cabin heat.
Hope someone knows something.

Well, yeah, sometimes the board can be quiet... You know, I wrote a how-to on rebuilding the posi-traction, spent a lot of time on it, like maybe 10 hours. I got one acknowledgement and it sunk out of sight. But, it is what it is.

To the point, the 1st gen ex runs cold. I have read threads about thermostats, burping, everything else. I do not get significant heat for the first 10 minutes, and it is a long time before I get really decent heat, like I might turn it down. I have suspected... well, I know, that diverter valve restricts flow. I'm up in Northern Minnesota, meant to replace it with some straight pipes last fall but I got caught up on other things. To improve heat, I would do just that... put 2 hose couplers in place of the diverter assy. I would open up the blower motor area and the blower resistor area and make sure it's not stuffed with leafs. Then, maybe I would replace the heater core on the theory that a 17 year old heater core might be a bit clogged.

I ultimately put in a seat heater and a remote starter.

 

[kkjb4x4.0]

Then, maybe I would replace the heater core on the theory that a 17 year old heater core might be a bit clogged.

]

Yeah that's my theory. I have and drove a 97 mazda with the 4.0 for 10 years, always had good heat, never had a problem with air pockets. I can't imagine the ex being much different. I think it's simply the heater core! Could be wrong though.