tag0617

I recently had a pinhole in one of my radiator hoses of my 1992 Accord 5-speed. I replaced that hose quickly, never let it overheat beyond 3/4 gauge temp.

Anyway, After replacing the hose, it still would overheat about a half mile into driving. So I replaced thermostat. That didn't fix issue. Fan switch is brand new as well for what that's worth.

I also have no heat -- I used to have heat so hot it would burn your knuckles.

So I removed the thermostat and ran it without one. Never overheated after 40-plus miles of driving. Went and exchanged thermostat for another new one. Put it in and half mile later ... overheating.

Removed thermostat again, drove 20 miles no overheating but strangely enough on a couple occasions the temperature gauge went to cold -- not the cold point to where the car is off, but to the C on the gauge. After a few miles it would come back to normal temp. It did this a couple times. Any ideas?

poorman212

And you are sure you have all of the air out of the system....how did you bleed it?

Dc4LsTeG

iTrader: (7)

Sounds like your not bleeding the system properly after installing the thermostat

tag0617

I've been bleeding it using the bleeder valve by the thermostat. I wait until a steady stream of antifreeze comes out without air bubbles and tighten it back down. Then I top it off. Am I missing something?

poorman212

Heat set to max, so the heater core can be filled/bled. The statement about NOT have heat leads to the trapped air.

tag0617

Yeah, heat is maxed. I did a flush and refill today to make sure of no trapped air. Bleed system as described with heat maxed until steady stream. Still no heat. I am at a loss.

Nickmg555

You might want to use an IR thermometer and check the temp of the coolant hoses in relation to the gauge. Simple enough to rule out a faulty temp. Sending unit. I had rapid temp. Changes as well and it turned out to be air in the line even though I bled it.

motegicivic

I am wondering if you have a clogged heater core.

Lost Again

Is it still over heating with the t-stat in?

tag0617

Yeah, even got another thermostat and it overheats within a half mile. Running it without one until I have more time to decipher. What's the best way to check or possibly fix a clogged heater core? Can I back flush it perhaps?

Lost Again

Yes but the whole system is in question now.

PT-Tuner.com

How old is the radiator cap? Are you sure your thermo-switches and fans are working? Are you experiencing any loss of coolant? Are you sure your not installing the thermostat backwards?

These are just some things that come to mind.

tag0617

Well I thought maybe it was backward, but it really doesn't fit the other way. Even though I'm sure. Thermostat has one end as a dome and the other a plunger. PLunger toward engine, dome toward outlet to lower radiator hose (yes?). That's how the one I took out was. The radiator cap was replaced when the leaky hose was replaced so it's about 2 weeks old. Switches are all less than a year old, one is a week old. Fans may be an issue, they worked until yesterday, now nothing. No coolant loss at all.

tag0617

Any more ideas?

Lost Again

Pin up on t-stat, correct.

Have you tested the fans?

I wrote something up a while back on the "workings" of the cooling fans for this gen.

tag0617

Yeah, pin is at noon. Fans were working. Now just one. Gonna correct that and see what I got. I'll have to find that cooling fan post.

tag0617

OK, fans are back working, but now this is what I got. The heater core is clogged -- back flushing it today. But also my car is now overheating without thermostat in. Not crazy but sometimes it spikes and now the overflow reservoir is filled. Do I have a clog somewhere else? Opinions?

tag0617

Interesting side note. I had to buy a lever vented radiator cap back a couple weeks ago, and most of these issues were increased since then. So today I ran the car with the lever up on the cap and i'm not overheating. Still no heat but i'm gonna re-install thermostat and leave lever up and see what I get.

motegicivic

I would try a reg radiator cap first.

You might have a headgasket issue.

Have you ran the car without the cap on, look inside do you see excessive bubbling? does the it overflow a lot into the overfill tank?

tag0617

With the lever down on this stupid cap, it has started to overflow a lot, with the lever up, overflow returns to normal. Without cap, a couple air bubbles but then it's ok.

motegicivic

Get an oem cap.

tag0617

Yeah, oem cap works. Back flushed heater core and got a significant blockage out. Heat works some now but still not like it used to. Thinking eventually gonna have to replace core but gonna run it some and bleed as necessary because this car seems to hide its air pockets well.