Mechanics

ENGINE RUNS REAL HOT

1995 Honda Passport

Engine Cooling problem
1995 Honda Passport 6 cyl Four Wheel Drive Manual 130, 00 miles

After driving about10 min or less, it gets hot. I feel the heat in the car. Also, when it is cold it runs good but as soon as it is hot the performance changes and runs rough. I had the thermostat changed but that did not help. The top radiator hose, thermostat housing and top of radiator get so hot you can't touch it, the bottom radiator hose is much cooler and you can touch it without getting burned whereas you can't put your hand on the top hose or radiator. The temp gauge goes from cold to 1/3 of the way up in less than 5 mins and stays there even when the engine gets hotter. Once it's hot the idle fluctuates ( goes up and down)when at a stop light and loses power as you accelerate. Also it acts like something is plugged up like maybe chocking on gas or maybe air or something. I took it to have diagnosed but they wouldn't tell me anything other than it was the thermostat but nothing has changed with the new thermostat. Could the radiator be plugged up? It doesn't seem like coolant is circulating.
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Marierussell
July 12, 2008.



Hi marierussell,

Since coolant is not circulating after replacement of thermostat, I suspect the water pump is faulty, you could have lost the turbines.

KHLow2008
Jul 13, 2008.
I got a new water pump 2 yrs ago when I got a new timing belt.

Tiny
Marierussell
Jul 13, 2008.
Hi marierussell,

Two years ago it was new, but now it could be junk.

It is not leaking but the turbines can go bad, detached or worn, seen plenty of those happening.

KHLow2008
Jul 14, 2008.
What are turbines and where are they located. Sorry I don't know. How do you tell if the water pump is bad? How long can I drive this before it breaks down? Do you think there's any water circulating at all? The overflow is always full to the top, I check it before I start it up and after driving when it is real hot. Do you think a new radiator cap might help?

Tiny
Marierussell
Jul 15, 2008.
Hi marierussell,

The turbine is attached to the water pump.

If the thermostat is open and water is not flowing, the main cause is the water pump.

If it is only overflowing into the reserve tank, a radiator cap change might help. Are the rubber seals on the cap worn or damaged?

Overfilling the reserve tank would make it overflow when the engine is running.

However since the temp gauge is showing high, It should not be the cap.

Remove thermostat and reinstall the hoses. Top up the fluid and start engine with radiator cap off.

If you can see the water moving in the radiator, it is flowing, if water remains stagnant, it is not.

Reving the engine should make the flow faster.

When an engine overheats, it should be repaired asap, failure to do so can cause a lot of damages if and when the coolant dries up while driving.

KHLow2008
Jul 16, 2008.
Ok, first of all, the temp gauge does not register at hot or in the red. It only goes up about one third of the way up from cold. It gets to that point in 5 minutes, in the morning after being parked all night. Later in the day, if it sits about 4 or 5 hrs, then, it only takes about 2 minutes to get one third of the way up from cold. It never shows hotter than /13 of the way up, not even half way, no matter how hot it gets. I can drive with the air conditioning on and still feel the heat from the engine.
The overflow bottle is above the max line when I shut it off an in the morning when I start. It never changes. That's the way it's been since I had a new thermostat installed. You said to disconnect the thermostat and hoses and then what? I got a little confused. I just don't think anything is circulating, really. I have to go back and read your reply. Thanks, will get back to you.

Tiny
Marierussell
Jul 16, 2008.
Ok, Did you mean to disconnect the hoses and remove the thermostat housing with the thermostat and then reconnect the hoses and let it run with the radiator cap off and see if it is flowing? I don't know that I can reconnect the hose with the thermostat housing off. Please explain again, thank you. : )

Tiny
Marierussell
Jul 16, 2008.

Tiny
Marierussell
Jul 17, 2008.
Hi marierussell,

Sorry if I have replied late.

The upper hose would always be hotter than the lower hose because the heated coolant from the engine goes into the radiator from the top and after being cooled by the radiator, it goes into the engine again via the lower hose.

From your description of the operations of the engine, there is nothing wrong with the system.

Do this simple test to find out if anything is wrong/

When Ac is turned, both fans must be working when the compressor is engaged.

Turn off AC and run engine till the fans comes on. If fans stops after a short while and then restarts again after a few mins, there is nothing wrong with the cooling system.

KHLow2008
Jul 17, 2008.
When I start up, the fan directly behind the radiator (clutch fan?) Is always on, it never stops when I'm not moving (in neutral), I don't know how to find out if if stops when I'm driving. I don't see another fan. For air conditioning. Don't know where to find it. Anyways, (after driving about 3 miles) when I start from a stop the clutch fan runs real hard kind of as if it's a really low geared vehicle, I have to shift into 2nd immediately and then 3rd seconds later. When I engage the clutch, it feels like the choke is on. Like I have my foot on the gas pedal. The fan runs real hard and real loud. It's really weird, maybe that's why I feel so much heat. I don't know what to do because when it's cold it runs fine until it reaches the temp on the gauge about 1/3 of the way from the cold side. As soon as it hits that temp, I feel heat inside the cab and that's when it runs rough like I described above.
What do you suggest? Have you ever heard of anything similar to this?

Thanks for replying,
Marie

Tiny
Marierussell
Jul 18, 2008.
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