killafred187

ok here 's the rundown i have a 1989 civic si hb. it is obd1 converted. i have wired the fan to run when the car is on. i have taken out the thermostat.
heres my problem when i drive at city speeds my car doesnt overheat but when i drive on the freeway the cars temp. soars almost to the top and the rpm fluctuates when i drive .
i dont kno what to do can some one help me please

~sp33~

Is putting the thermostat back in out of the question?

killafred187

well i have i just sitting there but how would that help (no offense)

~sp33~

None taken. Usually parts are put on your engine for a reason though.

If the thermostat regulates your coolant flow, perhaps it blocks the coolant to give it time to cool down in the radiator before circulating through the engine. Without the TS it would have less time to cool in the radiator?

Just a thought. Is it the stock radiator?

killafred187

yes and the rpm thing i have never seen before in my life except if i catually push the gas then let it go then do it again as if it wasint in gear but it is, help?

killafred187

cmon guys i thought u were honda experts

Dark_Teg

Put te T-stat back in. The coolant doesnt stay in the radiator long enough for the radiator to do its jobs without it.

This is gospel.

killafred187

alright and will this fix my erratic rpm problem or is that a diffrent cause

kit50si

had a similar problem try putting back thermostat and see if that will do. but my cousin said it's a headgasket problem. i put my car to rest cuz it was doing the similar thing.

~sp33~

Does your RPM fluctuate like 800rpm-1500rpm-800rpm etc? When your in neutral? If it does, search IACV and FITV, cleaning them is a good way to start.

killafred187

well i put the thermostat back in and it doesnt help but the rpm fluctuates like 500 rpm at a time, say if im going 3k in 5th it fluctuates to like 4000 then 4500 and back down to the regular time but i still dont know what to do? and ill try cleaning those sensors btw where are those sensors at? the rpm doesnt fluctuate when in nutrual (forgive my spelling)

killafred187

can it really be the headgasket? i just replaced it but didint know how to release the the camsprings( or put then bak on) so i didnt resurface the head so i just replaced the gasket.

88Hatchy

How fast does the rpm change? If it is really fast, then you may have a cluster issue.

ef-hatchcrap

Have you tried bleeding the coolant? You said you hard wired the fan is it blowing the right direction(sucking air through the bumber not pushing it out) it will work both ways.