lsv coolant temp rise.

i let my car warm up for 20+ mins and i see that it’s going above half on the guage. happens to me twice already.

i checked the radiator and i still see coolant. i turn on the car and its below again.

b18a1 with gsr head. i have a half size civic aluminum radiator with the greddy radiator cap. i also used golden eagle head-gasket 82mm.

i’m thinking the thermostat and probably take it off and run a bypass but need input on this one. need to tune my car very soon.

Does the car only overheat w/ the car stationary as well as driving? (not sure if you’re even driving the car yet since it sounds like you just built the motor)

Here is how I’d start gathering info:

  • determine when the car overheats. just idle? does it have to be revved? sitting vs driving? ambient temp?
  • is your fan coming on?
  • pull thermostat and test it
  • if needed, run engine w/o thermostat to see if it still overheats
  • if thermostat is not OEM or has not been replaced by you I would skip the above two steps and just install a new OEM one as a good “tune up” procedure

i turn on my car and let it warm up. i would come back in like 20 mins and i see the temp is over half, like a 3/4 before it reaches the H. i turned it off and checked the coolant and no leaks or what so ever. let it cool off for 10 minutes and turn it back on and its below half on the guage. so i decided to go test drive it and everything was normal. i drove like this for the whole day and no problem at all. my fan stays on all the time.

is their any cons to when taking out the thermostat? i was thinking about taking it out and run bypass permanently.

Sounds like the thermostat is not opening completely or just sorta working when it wants to. That’s not for sure, but probably the most likely.

You should re-wire your fan so it functions properly. There’s no good reason to have it running full time.

I’m not sure what you will be using your car for (daily driver, weekend warrior, track car…) but generally there’s no good reason to run w/o a thermostat. Some full race type situations may see a benefit from running w/o a thermostat, but really it will be situation dependent. Other than that there are only downsides.

  • your car will take longer to warm up, generally you want the car to warm up quickly, more wear takes place when cold

  • depending on the conditions you may experience over-cooling. This means you’ll be driving as normal but the car will be below optimum operating temperature.

Like I said, if the thermostat isn’t OEM or you personally have not changed it then I would just replace it no matter what. It’s one of those standard items which is good to replace on a fairly regular interval. Plus they’re cheap, why not just replace it and then be certain it won’t be an issue for some time to come?

oh ok. i did replace it and bought it from autozone…i forgot but i think i got the one in the 190s? my car is daily driven only. can it somehow be the headgasket because someone told me it might be the problem…

head gasket is possible, but i rarely see head gasket problems on b series engines.

I wouldn’t trust an autozone thermostat, eventually you’ll learn that if you go cheap on parts you will make your life a nightmare. I’ve had numerous occasions where non-OEM parts failed very quickly or plain old didn’t work at all right out of the box. I’d go buy a new thermostat immediately.

About a year or two ago I put an autozone thermostat into my Subaru. I don’t like to use those crap parts but the car was overheating on the way home from a vacation, was able to limp the car to my parent’s house. It was sunday night and I had to work early. Dealer wasn’t open so I got an autozone part hoping to just use it for the week until I could get an OEM piece. Got it all swapped out and went to drive home, only made it about 40min till it completely overheated again. Had to get the car towed and take it to Subaru the next morning as I had to work and didn’t have the time. Turns out the autozone thermostat was bad right out of the box. This is at least the 3rd or 4th time I’ve seen this in my personal experiences.

Is the water pump new? is the radiator new? does turning the heater on and running that full blast help at all?


brand new gsr water pump, new radiator, and no a/c or heater, all by passed. i guess i go buy the honda OEM then and seet he results.

i do smell coolant when driving but i can’t find any leaks anywhere…

what you mean jaydm?

u need to pressurize the system with a coolant test kit.

Hoseclamps leak alot of not very tight

pressurize to 13-15lbs and look for leaks it will be easy to spot, as u can hair it leaking and see it most of the time

u can also get coolant dye with uv glasses

today was weird. i was driving around 80 mph and i noticed my temp barely going up. it reaches to the middle and slightly drops back to normal again…what is going on???

Sounds to me like a air pocket stuck somewhere i have had this problem seems more present in ls v its basicly a air pocket in the engine where coolant is sposto be and when it moves to the area where the temp sensor is it reads temp is very low then it may jump up real fast when the sensor touches cooant and the air pocket moves

to solve this let the engine run with radiator cap off from a cold start and keep adding coolant to the top of rad as it goes down (it may bubble the pocket out slowly ideal) or very quickly so watch out hot coolant burns it may shoot out. Let it run until fans turn on usually 15min but if your fan is wired to be on all the time leave it off till your gauge reads little over half

with fans on all the time it may not get warm enough to move the coolant bubble through the eng and to top of radiator (like i said i had this same problem in my lsv with fans on a switch (on all times) my car on the highway on a trip it never got hot for hours and with in 30 seconds it was over heathing smelled like coolant all the time and temp was very eratic at the gauge bleeding the air solved this

i dont think its the air pocket because when i leave at idle for 20 mins or more…my temp guage go up and would not jump back down.

You most likely have a leak

Once again get a coolant test kit
and pressureize the system

have you tried bleeding and burping the system. i have a lsv and i had this problem a few times after the swap with the coolent. i know it’s hard to believe but the air pocket somewhere can really do it. let it run and warm off with the cap off and squeeze all the hoses as much as you can to try to get air out.

its gotta be an air pocket or a bad thermo, sounds just like the problem i had till i had the system bled properly. good luck

can the half size aluminum radiator have to do with my coolaant problem? i am using the 92-95 civic radiator and was thinking about putting back the original DA radiator.

b series should be able to run just fine on a half size radiator, people do it all the time. Of course every situation is slightly different, so I can’t say 100% that your exact setup is OK. But really no reason to believe it wouldn’t be.

well, i did the air pocket probelm and so far no problems for now. still using the autozone thermostat.