91 Honda overheating, I'm stumped
 

Hi folks,

I have a 91 accord LX sedan. When driving on hwy my heat gauge starts to move up to 3/4-7/8 level. This is without A/c on. When stopping, the car radiates heat seems to be much hotter than it ever was. Checked bottom hose to see if thermostat was allowing coolant through and yes its very hot so seems to be working. Replaced radiator cap. Coolant bottle is filled and gets warm so water is circulating thru cap to bottle.
Now strange thing is when I turn on my car heater on to hot air the gauge goes back to half way, but I sure get warm in the car especially when its 35* outside. Also when doing this the engine actually seems to cool down noticably. Can anyone suggest a fix or what to look at. Thanks.

i would say one of the radiator fan switches are blown. the reason the car cools off with the AC on is because when it runs, the AC overides the fan switches and turns on the fans, alowing the engine to cool. have the switches tested.

one of the switches is between the termostat and engine block. i bet that is wrong, becuase it should turn the fans on at 189

Thanks for the reply,

Both fans working great, checked them out. Problem is I don't use my AC, its when I turn the interior heater on and set to the hottest level that the gauge goes down and engine seems to cool down. I can't figure it out. Sure is nasty driving around when the weather is 35* and I have to keep my heater blowing hot air. Thanks for the tips but this is something else. Any other suggestions would be welcome.

hmmm, ok when you turn on the heater the coolant goes thru an extra radiator helping the car cool better. maybe it's your water pump going out on you, or there is a leak somewhere in the engine. Ok here are all the causes that could lead to overheating:

*not enough coolant
*radiator core broken or grille blocked
*faulty thermostat
*radiator cap not maintainig propper pressure
*incorect ignition timing.

have the thermostat and the cap checked first (assuming that you checked the fluid before posting).

Thanks again. Ok, new radiator cap so thats been checked, no coolant loss, I just did the timing 2 weeks back so after all this........................even though my bottom hose is heating up which leads me to believe the thermostat is working this is the only thing I haven't taken out and checked. I'll just replace it and let you know the result. Thanks very much for the suggestions...........

what about the top hose ?

Hi,
Top hose hot about same temp as bottom. Could it be just my temp gauge is shorting out somehow ?

maybe the termostat does not open when it needs to, or it does not open enough. have that removed and see if it overheats

my 93 accord ex is having the same problem I can't figure out why it is overheating for the life of me! I've changed the sensors and my fans work but somehow it is still overheating, George I feel your pain for the past month or so I've been driving around with my heat on! I think i'm finally going to give up and take it in to the shop.

Hey John with the 93 please let me know if the garage discovers what it is.

Okay I have just finished checking ( for the second time)fans, fan switches temp gauge and all are okay. Correct readings from all. I still haven't replaced the thermostat yet will be doing it this week-end and will tell you if it makes a difference. One other thing I turned on my A/C yesterday and as soon as I drove for 15 minutes over 80km per hour my heat gauge went into the red. I experimented by turning off a/c and gauge went down a bit. Then I turned on my interior heater and gauge went back to normal. I then switched back on the A/C and and I slowed down to 50 km per hour and gauge fell nearly to half way level. As soon as I speeded up the gauge went back to red. .AAArrrghhhhhhhh.

THERMOSTAT, or the tranny is going out. i know case when the car would overheat because of the tranny. also is it a manual ? on my subaru, turned out that the clutch was slipping and when there is slipping heat is generated, thus sending the water temp on the red level

I think I've found out what is wrong with my car! I've come to the conclusion my waterpump is bad. I took off the radiator cap (when the car was cold) and turned the car on and the coolant was just sitting still not moving like it should. I guess I'm gonna replace the water pump now. George try taking off your radiatior cap and check the coolant flow. Also, I unplugged the coolant temp sensor and stuck a paperclip in the two sockets and both fans kicked on immediately. Will let you know when new water pump is installed.

Thanks for the tip about taking the cap off. I'd be surprised if my water pump has gone as it was replaced 3 years ago when the new timing belt was put on. Hondaman I have a manual and there is no evidence of clutch drag//slippage. Clutch plates were replaced 5 years ago and all gears and clutch appear to work fine.

Picking up a new thermostat at end of week and will throw in a new fan switch when replacing it. Will look at the fluid with radiator cap off right now. Cheers

on my 92' prelude S(f22a1 engine) it would overheat.. turned out the water pump was going.

Turned on engine removed rad cap and after 10 seconds coolant started flowing over the lip so pump seems to be okay. Back to the thermosat.

Engine has to be cold for several hours when you check this and it should not shoot out unless your car was hot!