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Heating Problem (or not)

1089 Views 6 Replies 2 Participants Last post by  Bodie43
You guys are so good, thought I'd pick your collective brains a little further.

Car starts and temp gauge is at "C". After a few minutes it goes to approximately mid-range, which I assume is normal. After another 10-15 minutes, under normal driving conditions, regardless of ambient temperature or A/C on or off, temp shoots to almost redline ("H") and meanders back and forth between real high and REDLINE.

Initially I thought thermostat. So I changed it. No difference. Fans were coming on and off at about 30 second intervals and radiator was cold telling me that the fan(s) are doing their job by what they are seeing from the thermosensor.

Now I'm thinking water pump. BUT, the car drives just fine, no perfomance change as you usually see from a hot motor condition, and no boiling over even though the temp gauge ventures into the red range frequently.

Now...what about the temp sending unit? Am I possibly getting a bad signal to the gauge, or maybe just a bad gauge?


Any of you smarties care to tackle this one?
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This sounds like a classic case of air in the system. I have spent countless hours looking into and dealing with this subject on my '92 coupe.

Try letting car heat up and as it is doing so, bleed the air out of the bleeder valve at the top of the thermostat housing. You just barely need to crack it and it will start spurting air, once it is solid fluid you should be good to go. This may take up to 30 minutes or so as you need to close, bleed, close, bleed, etc to get all of the air out of the system.

Keep rag handy to dab the fluid and control the "splats" coming out of the valve.

Does this all make sense??? Know if you keep getting air in the system, like my car is doing you need to find out why. Sources are, bad cap, leak in radiator (which I have), leak in hose, etc. It could be very minor and not hardly noticeable even.

emial me with any specific questions you might have. Also, let me know if this solves your problem.

Good luck.
Thanks for the tip. Sounds very feasible. I am going to try that as soon as I sign off. I will report the outcome.
Just opened upthe bleed valve and got nothing but solid fluid. No air whatsoever. BUT, the fluid that came out was barely a trickle. I opened the valve almost a full turn and still only a trickle of coolant.

I squeezed on the top radiator hose while I had the bleed valve open and coolant shot up about 6 inches..... This tells me it's either the coolant pump or the radiator is just plugged up as i'm getting no flow or very little flow through the system.

Just looked at my Chilton's manual and it looks like a real ***** getting to that water pump too.... <SIGH>

Thanks again for the tip.

Ok let's try some more.

Is the bottom radiartor hose getting hot after the car's temp is reading hot?

You say the fans are cycling like they should.....

You replaced themro.

You may try replacing the cap with OE, but if there is pressure buildup it probably is not this, but in the process of ellimination.

I would assume that when the 90k serice was done (timing belt etc) that the water pump was changed at the same time? Or at least it should have. Unless it is leaking this is most likely not it. The fins on the thing would have to be worn down and that would take a lot of errosion.

I assume there are no leaks? How has the condition of the fluid been? Clean? changed yearly, etc? Ie clogged radiator possibly?

Yes there are a couple of sensors, lower radiator (but since the fans are comming on probably not this one), there is a gage sensor on top of engine as well (at least on my '92).

This is so classic air in the system symtoms, that I was sure that would be it, but you say you didn't get any air at all out so it doesn't sound like there is any in the system. The acuras are very sensitive to this for sure.

Well that is really all I can think of at this point, but do keep me posted as I'm going to be changing out my radiator to keep mine from having heating issues and sucking air into the system. It doesn't leak enough to drip, but you can see seeping on the lower tank of radiator and air eventually gets in.

Keep in touch.
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Hey NCallegend....

I just bought this car two weeks ago so I'm not sure of history as far as 90K service. The way it looked, the guy didn't take too good of care of it so I wouldn't assume anything as far as regular maintenance. He was a young guy who just bought himself a 325i and just wanted to dump this Acura. I spent a week rubbing out the oxidized paint and cleaning burnt brake dust from the aluminum/chrome wheels...But it was such a good price ($2500) from the others i looked at, so i couldn't pass it up. Mileage is 149,000.

The car doesn't leak ANYTHING. No indication of overheating either- i.e. THAT SMELL of heat, or lost performance. The gauge wanders into red zone but never actually boils over or stays in red for long. It is usually running in the area just at the "h" point on the temp gauge. The reason i don't suspect bad gauge is that it starts at "C" and goes to midpoint for a few minutes of driving before it shoots up to hot.

My final attempt before surrendering and taking it to dealer (maybe Honda instead of Acura?) will be to change radiator cap per your last suggestion.

Thank you for your interest and help. It is greatly appreciated.

Bob Beaudette
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Oh, I forgot to mention bottom radiator hose....

I haven't touched it yet. I will do so today.
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