Thermostat not opening?

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Korax

Member
This question is for my 90 DX hatch with a non-vtec JDM D15b (supposedly its originally a dual carb motor that is now running on the stock DX DPFI system). I bought this car at the begining of the summer. The previous owner used this car only in the winter. When I got it I found that the cooling fan was never coming on. The relay is good so I assumed it was the thermo switch. At the same time It didn't seem like the Thermostat was ever opening.. as the lower rad hose never got hot. So I took the old thermostat out and wrapped a wire around the thermo switch so the fan was on all the time. It ran rich and had one of those typical Honda idle problems when it would occasionally reach close to operating temp.. I just assumed it was because of how the cooling sysytem was.

Now a couple of days ago I replaced the thermo switch (Honda) and thermostat (Autozone/mart something) with new ones. I have let it run and have drivin it and the thermostat is still not opening (lower rad hose still cold) as well as the fan still isn't coming on. It seems to be idling fine now (around 1-1.2k). The coolant has been bled so I don't think there is an air pocket or anything. I didn't think it would make a difference with how the two wires on the switch were connected but I switched them anyway and it did nothing. I switched the relay with two other ones and that isn't doing anything either.

The vehicle was also originally A/C equipped but when I got it it had no lines or condenser. So I also took out the fan for it and the little radiator..pretty sure I left the relay attatched but I'll have to check. Idk if that would make any difference either.

Any ideas would be awesome. It doesn't seem like its getting too hot but I'd rather have it work right than risk an engine blow.
 
its not uncommon to get a new but bad thermostat from autozone, best way to kbow for sure is take it out and boil it in water on the stove and see if it opens, but im guessing its not going to. sounds like a new but bad one to me
 
Hmm.. I never thought about boiling one to see if it opened. As much as I hate to dump all of my coolant back out I think I'll try that tonight.
 
yeah old school way lol, make sure its not in upside down to. it happens even with pros
 
Ok so the thermostat was in the proper position and I just boiled it in water. It opens. /stumped. Is it possible my engine doesn't get hot enough? It just doesn't sound right, but I don't have one of those cool laser thermometers either ;x.
 
Ok so the thermostat was in the proper position and I just boiled it in water. It opens. /stumped. Is it possible my engine doesn't get hot enough? It just doesn't sound right, but I don't have one of those cool laser thermometers either ;x.
it happens sometimes, just put it all back together and just run the car and see if it ever over heats, you could always buy a lower temp thermostat
 
I'm thinking about that too vtec... When I shut off my car the coolant res. just gurgled and shit for about 30-40 minutes... Is this a huge issuse or what? My car never overheats either. I'm fuckin stumped as hell on it...

Don't mean to thread jack but hell, it's sort of on topic along with the OP, so I don't quite see the need for making a new thread.

EDITED lolz
 
Hmmm only thing that really makes me paranoid tho is that it gurgles/boils... but my temp gauge reads the normal op temp... IDK tho it hasn't made any reliability issues at all so maybe it's just talking shit lol
 
Hmmm only thing that really makes me paranoid tho is that it gurgles/boils... but my temp gauge reads the normal op temp... IDK tho it hasn't made any reliability issues at all so maybe it's just talking shit lol

If there is any one thing I'm paranoid about in a car, its the temp. I'm always watching that gauge ;x.

I took it out on a nice drive last night. The fan did come on for a minute so I now know that it does work properly. Yay. That damn hose was still cold though.. just wierd.

I may do what you suggested and get a racing thermostat. It's just wigging me the fuck out, thats all ;x. Thanks for the input. Oh, and that wasn't much of a thread jack lol.
 
your coolant isn't overly diluted is it? if you have too much water in there it will start to boil out through the overflow tank.
 
I'm gonna flush and refill my cooling system some time in the next couple days, and see if it goes away. Also gonna get a new thermo just to be safe. The one on there is the one it came with from the factory. It has the date of mfr stamped in it. 1/15/04 lol
 
Is there a gasket in the thermostat housing? I had a 88 DX hatch and someone put a new thermostat in but not a gasket so coolant could easily pass by, it was cold 24/7.
 
Mine has a gasket, or seal to be exact... I went and got the part today, and didn't realize the whore at advance gave me one for a 95-99 neon, which has it as part of the fucking radiator cap! On newer SOHC neons it's not.
 
Is there a gasket in the thermostat housing? I had a 88 DX hatch and someone put a new thermostat in but not a gasket so coolant could easily pass by, it was cold 24/7.

Yeah, it has a gasket, with the tabs lined up in the proper place. The rest of the system def gets hot. But over the past day of driving it (during the day) it still has not opened. While it is not having the bouncing idle problem anymore the revs don't just drop like it is supposed to. When I shift it will stay at like 2-3k and then slowly drop back to 1-1.2k.
 
but I don't have one of those cool laser thermometers either ;x.

Oh Oh Oh!! i do i do!! and boy are theyyyyyy fun :D

hahahah.

My turbo manifold is 554 degrees :eek:

But that does sound wierd, have you managed to get a new racing thermostat in there yet?
 
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Oh Oh Oh!! i do i do!! and boy are theyyyyyy fun :D

hahahah.

My turbo manifold is 554 degrees :eek:

But that does sound wierd, have you managed to get a new racing thermostat in there yet?

Nah, I haven't yet. I don't have the extra cash atm. It still isn't working right but it's still not over heating either. Hopefully I'll get it worked out by this weekend.. if not, I'm gona try that lower than 180 degree thermostat.
 
did you jump the fan wires to the battery to see if the fan motor is working properly.the coolant temp switch might be faulty and its not giving you a good reading.
 
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