Here is the issue I have. (the car is a 2000 si with b16) My car drives fine for about a half hour, then starts getting hot. The coolant is full, when it starts getting hot the coolant resivoir gets full and starts over flowing. The fan is on a maual switch so it's always on. I do not have a thermostat. With that said the car should not be getting hot, and it never has until recently. No smoking from exaust or valve cover... No oil in coolant.

Some things I'm conisidering could be wrong but I'm not sure...
-I changed the coolent temp sensor on the head

1.Radiator Cap
2.Cooling system clog
3.Head gasket
4.Cracked Sleeve

What do you guys think? Where should i start, the obvious cheap fixes come to mind first, but i'm wondering if anyone has had experience with the same or similar issue.

BTW I'm having an issue with the car idling when cold and my lights on my dash dimming. But when the car starts to get hot above normal, the idle goes smooth and the lights don't dim at all. In fact the car runs a lot better.

Any help is appreciated.

 

ttt

 

I would get the engine leak down tested for a blown head gasket.

 

you should also put a thermostat back asap that will fix your idling problem

 

I'm doing that this weekend to see if that is the case... but wouldn't i be burning or mixing oil and coolant if the headgasket was blown?

 

How does the thermostat not being there affect the idle?
(not being a smartass... i just have never heard of that)

 

Well you should put the thermostat back on because cold coolant quickly mixing with a hot head will cause a "cracked head". That's kind of strange how your coolant is still being shot into the reservoir tank even though you removed the thermostat. Strange indeed.

A little history on the motor? Is this a swap? how long have you driven it before this started happening?


If I remember correctly, your IACV is responsible for your idle at the beginning. It helps raise your idle until your coolant is up to temperature but since your removed your thermostat, then its probably always cooler than usual. Correct me if Im wrong anyone

 

so many different answers...so what should I say??? Your radiator is old and dirty get a new one. thats all I got.

 

The thermostat is there for a reason. It's usually used to slow the flow of coolant circulating through the block. The flow of coolant is slowed because it gives it time to absorb heat from the block. When you remove that restriction and allow coolant to circulate unobstructed, it doesn't have the same amount of time to absorb heat as it did with the restriction. So, while your engine temp gauge may have been showing a 'normal' temp, your engine was probably running a bit hotter than you thought. Wiring the radiator fan to always be on may help marginally but the only thing you're doing is wasting its life because it was never meant to run continuously.

Put things back to how they should be and go from there.

 

The motor is a b16... its the one that came with the car. I upgraded the rods and pistons... I have GSR cams and ported and polished head... The car is boosted and tuned... I've ran like this for a year and a half without any issues and parked the car for the winter. It's tuned on E85. Everything has been perfect until i started it for the first time this year and took it for a drive.

 

I was thinking that it might be clogged or something... I will replace it and see if it solves the issue...

 

IS THE RADIATOR FAN coming on?

 

Oh, then its probably frozen or clogged up. Here's a story I had with a swap. I threw in an h22 motor in my car. It hasn't been started since 1996. Anyways, long story short, after I started it, the dam thing kept overheating and shooting hot coolant into my reservoir. I tested out the thermostat by boiling it and I see that it opens. After that I put it back in, re-bled the system, and left it running for a bit. It stopped shooting hot coolant into my reserve tank. I think your problem will go away soon, just let it warm up and maybe the clog will unclog due to the heat pressure. However, you don't have a thermostat so it may take longer to heat up. I would recommend putting on the thermostat back on. Boil it first in a pan of water to see if it works.

 

flush your radiator.

 

I was told E85 cooks your motor if it was not originaly made for it and if you daily it. But thats just what I heard and I never used it before so just letting you know.

 

you most likely have low coolant or a block in your cooling system. take radiator cap off, get a water hose, fill radiator while simultaneously revving the motor from the throttle body, this will effectively clean your system of any gunk in the system.

water is just fine for a car in spring/summer/early fall. as long as it's not freezing outside, you can use water.

 

ok so lets get the down low on the Thermostat the way it works is to limite the amount of
Coolant the motor heats up till all the coolant is at the same temp.
the cooling fan switch dosent turn the fan on till it reads 210~212 deg (Info for a 95 Del Sol from the Mechanic at the dealer)

a stock thermostat for Most hondas is 185 and the water pump will keep the water flowing throught the head and block at all times till it gets to that temp at the thermostat (will also flow throught the heater core if heat is turned on in the cabin area of the car.) Once the thermostat reaches temp the the 185 Deg coolant in the block is replaced with teh Much cooler coolant from the radiator (ever seen the temp guage drop after you first start your car Thats why) the thermostats drops temp the the cooler fluid reaches it and the prosses starts over till all the coolant is about the same temp. one the coolant is all about the same temp the thermostat stays open Most of the time and acts as a rstricter plate slowing the flow of coolant to the radiator alowing more time for the radiator to disapate heat from the coolant.

with out a thermostat your car will run cooler but this is do to the fact that it is trying to heat up ALL the coolant at once compunded by the fact your Rad fan is always on it will take longer to get the coolant up to temp. the IAC and the what ever the hell that thing on the bottom of the throttle boby is. Both help the car idel when cold by controling the amount of air that let past the throttle body butterfly. this is how the Thermostat is related to you idle.

Also witch temp sensor was it you replaced the 1 wire sensor for the Guage or the 2 wire sensor for the ECM. i had a bad sensor for my ECM it was 45 Deg out side the coolant was cold but the ECM showed the coolant temp was 176 Deg. i put a new sensor in and Bingo smooth idel again. i never got a cel cuz 176 is inside the normal temp rang for the sensor.

Look at the motor oil. if it looks like a Milk Shake it a Head gasket or craked head.
also is your turbo oil or water cooler I'l say oil as water cooled turbo are not that common.

WHAT!!!!!!
ok lets think about this

Water boils @ 212 Deg

Ethylene glycol (common green cooliant) boils @ 387 Deg (100% No water added)

at a 50/50 mix Water to Ethylene glycol the mixter boils @ 225 Deg

plus the added 7 Degs per 1 PSI in the cooling system.

E85 Is just fine For a DD if you Tune the car for it.

Not a Bad idea. but i would use a Back flushing kit and put some CLR or Lime Away in and let it run for about 20 min or til the motor is up to temp and the thermostat has opened

also get the New blue coolent Honda has. i'm getting Better heat transfer from the heater core and Radiator Pluse there was less evap coolant loss over the green crap. and a Bonus it's the only New style coolant that will Mix with Green coolant with out gelling

Try reading the Post befor you start typing.

 

my car runs perfect and has done so for the last 277k miles... your numbers are fine and all. but i run what i know.

I flush with water, drain, refill with honda coolant.

if there is no coolant around, water is safe.

 

Thanks for the advice. I will get the new coolant from Honda and give it a try. I replaced the temp sensor that goes to the gauge. I don't have anything plugged into the other temp sensor as it controls the fan... and my fan is on a manual switch. I just got a new thrmostat today I will put it in and see if the idle gets smoother.

Would you recommend replacing the radiator with a used radiator? I found one locally for 40 bucks which beats the hell out of the $300 dollar dealer price...

 

Buy a new ebay one. Ive never had problems with ebay oem type radiators.


Could be something as Simple as heater core is clogged. Did you ever add "Stop Leak" or w/e its called to your coolant. If so thats a problem and a half.

 

No I didn't add any stop leak junk, I've never had cooling issues before... even this issue takes a while to happen, so i'm thinking that it is a clog somewhere...

I looked on ebay and saw some all aluminium radiators that are oem dimensions, I just need to make sure the stock fan will mount onto them...

Does anyone have any experience with these?