DavidT

Sometimes the car will start to overheat a little. Reach the middle and maybe 1 bar over it on the temp gauge, but will go down if i drive normal. When i turn the heater on, it blows cold. The electronic part of the heater is fine as in the heater core part near the battery is opening and closing fine.

It seems it happens after I get into boost. We changed the themostat and bleed the system but it could be a bad themostat or not a good bleed. Maybe the mishimoto radiator is causing it.

My guess would be to change the themostat one more time and bleed the system the best i can and put the factory radiator back in. Worst comes to worst, change the headgasket.

Oil looks fine with no milky substance and car doesn't smoke.

Car info.

2005 s2000
Comptech supercharger kit / after cooler
81,000 miles
usual bolt ons
no check engine lights.

ryan_1014

sounds like you are low on coolant or clogged heater core

JulieU

Dunno if this will help any or not, but might be worth a read thru...

Having Coolant Issues - Mishimoto Install

DavidT

update. got it. The rad cap was bad and im sure the bleed was too.

bigmacnfries

thanks for the update dude..

jinkyjank

I wanted to add my experience with my 2007 Honda Accord.


I was having intermittent overheating issues combined with a non-functioning heater. I believe that there is a direct relationship between these two issues. It is likely that when your car overheats there is a mechanism whereby the car stops the flow of coolant to the heater core. This makes sense as high temperature coolant could damage the core and lead to high temperature fluid inside the cabin. Therefore I determined that it was likley an issue with the cooling system.


I added coolant to the max line of the reservoir tank and I still had the issue. Then I let the car cool and then checked the fluid level and added more Genuine Honda coolant directly into the radiator by removing the cap. I started the car cold and followed the procedure that you would follow to fill the cooling system after a flush. The radiator accepted a considerable amount of new fluid. This solved the overheating and heater issues.


It is likely that I have a small hole in the radiator and that it will have to be replaced. I let the reservoir get low enough that the radiator was unable to pull fluid back into the system properly and this permitted low levels of coolant in the system leading to sporadic overheating and heater core shutdown.



If you have similar issues then make sure your car’s cooling system is functioning properly before you move forward with costly heater core repairs. You can use an infrared thermometer gun ($20 Amazon) to help diagnose problems and this will save your considerable time and money. There are many guides on the internet to help you with the diagnosis process.


Troubleshoot Engine with Infrared Thermometer

Bryce Abell

i am having this exact issue with my 2006 Honda Accord, pulled over driving home from work when I saw the temp gauge rising and found almost no coolant. I added enough to the max line on the tank, but after waiting a few minutes and then going on my way it kept rising to about 3/4 of the way before dropping. I did not have any heat as the last guy said. It continued to happen until about 30-45 minutes after I filled it with coolant.

was my car that low on coolant it took that much time to go through the system? I’ve now been driving over an hour and checked the coolant and over half is gone. I don’t think I have a leak but can’t tell today as it’s raining here, will report back on that.

Awesome thread guys thanks a lot!

philiam

There may be air is the system in which case it will need to be bled following directions. You can probably find a link on Utube.