legacycentral bbs

i was curious about this. It seems that the fan is only coming on in D check mode. Any ideas?

Here's why i noticed.

Yesterday my wife drove my SS to work and about an hour to an hour and a half another employee came inside and said there was a huge puddle of coolant under my car. Well i went there and looked at it and sure enough there was a huge puddle of coolant. As far as i can remember (now that i think about it) i don't think i have ever heard my fan come on. Also i haven't over heated either

She said it didn't over hear but it was obvious it did, but not enough to do damage. Anyways, i checked the heads and didn't see any coolant. I'm thinking i may have a bad thermo, but i topped the car off with coolant and it's been fine ever since. I checked the oil and no coolant. this weekend i'm going to pull the plugs and inspect them.

I don't understand why this would occur at all. I just did my head gaskets when i finished my DOHC swap. I used Cometic head gaskets.

Car has been running great tho. Any input?

Which fan comes on with the D check? Is it both or just the passenger side? The Driver's side fan should come on first with normal usage but both with D check if IIRC, also typically you will not find oil in the coolant with headgasket issues, it will be HC in the coolant, when running the car right before the fan comes on when looking in the overflow little bubbles will start forming and that is HC in the cooling system. Also there will typically be no signs on the spark plugs. Were the heads checked for warpage at all? Was the cooling system burped properly?

i only have the driver's side fan.

the heads were not checked before installation. I bought a full ej20h motor from jake at PIA. It was fully assembled when i bought it and didn't feel it was necessary to have them inspected.

my DOHC conversion has been completed for almost 9 months now, and i have put thousands of miles on it.

and i don't recall the fans coming on unless it's in d check mode.

D-check mode simply checks the relays. If the fans are not coming on, you likely have a problem with the coolant temp sensor that goes to the ECU. A stuck thermostat would still cause the fans to come on.

I'd suggest replacing the coolant temp sensor.

i'll look into it then. i swapped coolant temp sensors when my first injector crapped out on me about 5-6 months ago. maybe i just buy a new one.

I would recommend that. They're around $20 new.

wouldn't a bad temp sensor cause the car not to start and throw a code?

Not necessarily. They can get lazy and instead of changing resistance, they may just hang around the same spot. It all depends on where they get "lazy" and fail. Our ECU's are pretty dumb and don't have logic built in to throw a code if the ECU is not reading a certain temp after a given warm up time.

if i have another used one sitting in my garage should i try that first?

it's just weird, now that i think about it, i cant recall my fan being on at all lol.

If you have another one, yeah go ahead and try it.