Thermostat Question

What could occur if I drive my 94 EX Coupe without thermostat?, now I'm driving in a very hot place.

if you drive in a very hot places . you need no to install the thermostat, because you need no hot engine but you will need to cold the engin.
but make all thing carfully and after finish be sure that the fan is work.

Driving without your thermostat could cause your ECU to go into an open loop and you'll lose gas mileage. I think the original cooling system of your car is fine and you should drive with a thermostat even in very hot climates.

Driving without your thermostat could cause your ECU to go into an open loop and you'll lose gas mileage. I think the original cooling system of your car is fine and you should drive with a thermostat even in very hot climates.Well said. Your engine will basically try to compensate for the cooler engine. In turn the engine will run rich which will cause other emmission problems in the long run.

Your engine needs to run at a certain temp and that's what the thermostat is for, running without it will cause your engine to run to cool which will cause sludge build up in the crankcase which in turn will cause blocked oil passages which could lead to engine failure.

Leave the thermostat in a add the right coolant mix (most likly a 50/50 mix) and your engine will run like it should.

Alright guys, since were on a thermostat question. I just installed my thermostat and the engine starts to over heat and starts to surge when i put in the clutch. Then when i turn the heat on there is absolutly no heat. I shouldnt say "surge" but goes up in rpm and then drops down and then up and then down very fast like it's trying to warm up but then it relizes it's to warm and lowers rpm and relizes it's to cold.

im not sure but can anyone help? And i just replaced my thermostat so it had something to do with that but im not sure if i missed something or what. So please help.

Is your fan coming on? How is your coolant level? Did you make sure to get all the air out of the system before putting on the radiator cap (after the thermostat change)?

my fan works fine. and my coolant level is fine, but i never let all the air out. how do i do that?

Take the cap off (when the engine is cold). Let it warm up to where the fan kicks on. Rev the engine a little bit, if coolant is spraying everywhere (out of the top of the radiator) then don't rev it that much. And you should see air bubbles coming out the top of the radiator. A warning though, you're probably going to get some cooling that will spray out, so you might want to put some rags around the top of the radiator. Eventually all the bubbles should be worked out of the system. After that, maybe check your water pump.

I did that and it worked. Thanks a lot dude.

The only reason I changed my thermostat was because it took FOREVER for my car to get warm. So someone told me to change that and i have not tried it out but i am trying to be optomisitc.

Does that sound like something that could be wrong or no? because my friend has a 1.6 mazda mx-3 and his car takes no time to warm up. So i was just tryin some stuff out.

And anyways, would a thermostat for a 92 - 95 work in a 88 - 91 engine? or the otherway around?

Glad to hear you got it running right. One thing you have to remember is that you have an aluminum block, so it will take quite a bit longer to get it warm. It usually takes my car 2-3 miles before it fully warms up, of course that's starting it up and just going. Not really sure about the compatability. Autozone's web site seems to have some that share the same part # and others that don't, and I have no personaly knowledge on it.

I guess that makes sense, But the problem is that it takes me like 4 - 5 miles to START getting warm. Then after that it raises slow'y but never gets up to the middle of the temp gauge. But my heat is fine.

In one of the posts above, the person said that if it runs cold it will cause the ECU to go into an open loop and cause bad gas mileage. Is there anyway to figure out why my engine isn't getting warm?

Honda engines don't get that warm to begin with. My temp gauge never gets near the middle, usually between quarter & middle. If i'm going down hill my gauge usually bottoms out. I wouldn't worry, I have a 93 Civic EX with 200,000 miles and it gets 37-40mpg and i haven't done a thing to it in 65,000 miles.

Oh really? Alright sounds good. I thought there was something wrong. do you think the d16z6 gets better gas mileage then then d15b7?

No, the d16z6 ecu (p28) gives it more gas when it hits vtec. But it also depends on what tranny you're using.

And how you drive.

what is the difference with the different trannies and the p28?

nah, i drive pretty nice. I don't like to waste my gas considering i drive to school and to work and there both pretty far away

the p28 is the vtec ecu and it comes with the d16z6 which should be in my 93 civic ex but i tihnk i got maybe a 90 or 91 d15b7. So i dont think im ever going to get better gas mileage unless i do a swap. i heard the b series give you better gas mileage considering they have more horsepower and it's easier for them to get to that 5th gear.

what is the difference with the different trannies and the p28?
The longer the gears, the better the gas mileage. For the 5th gen civics, from longest to shortest, CX/VX (the same gearing I believe), DX/LX, Si/EX. However the longer the gears, the less acceleration you will get. So there is somewhat of a trade off between fuel economy and performance.


the p28 is the vtec ecu and it comes with the d16z6 which should be in my 93 civic ex but i tihnk i got maybe a 90 or 91 d15b7. So i dont think im ever going to get better gas mileage unless i do a swap. i heard the b series give you better gas mileage considering they have more horsepower and it's easier for them to get to that 5th gear.
The d15b7 only came in the '92-'95 civics, you sure about the engine code? But the B-series will give you less mpg, because they are bigger engines and have more power. The bigger the engine and the more power it makes, the more gas it needs to run. Even the B18b1 (Integra LS, RS, ang GS engine) only has 140hp and the longest gears of any b-series transmission, but it will use more gas than any D-series engine (regardless of transmission). And 5th gear doesn't mean anything really. As long as you're in a high enough gear that the car isn't bogging (caused by being in too high of a gear), you'll be getting the best mpg possible.

what was the engine codes that came in the 90 - 91 civics? I'm pretty sure mine is a d15b7 but it doesnt look like any other d15b7 that i have seen in like a DX/LX or maybe a VX/CX. I'm not totally sure though.