1999 Honda Passport, my daily high millage beater is giving me fits with a over heating problem. For a couple of years in very hot weather(100+) while climbing a long hill it would start to heat up especially if the AC was on. Usually I got by by just turning off the AC or if it was a really hot day I would turn on the heater till I crested the hill and that would do it.

There is a heat gauge but it is typical cold/ hot with no temps listed with just a red area as the indicator nears the H.The other day unbeknownst to me I developed a split on the upper radiator hose as I started up said hill and I didn't catch it till I heard pinging and and smelled anti freeze, engine was very hot, pegged passed the red and onto the H. After a 15 minute cool down I made it to a place where I could get water( 1/4 mile) and cooled it down to a normal temp. I did a repair on the hose and made it home about 15 miles, gauge was getting close to the red area again and it rumbled but did not puke any water out the cap.

With the cap off I see no air bubbles in the radiator and I have ran it 25 miles or more down hill or flat and it hasn't heated up but I can't pull a hill without heating problems. What do you think, bad radiator, stuck thermostat, blown head gasket or what?....Tedd

 

Slippin trans if its an auto. High miles, maybe the rad is plugged up down low with sediment. Hoses collapsing. Feel the tank temps down low compared to up high when it does this. Of course the easy starting point would be the stat, a flush and new hoses. Disconnect the heater core and flush it separately with low psi from garden hose.

 

My money is on a bad radiator, you are describing classic symptoms of a partially plugged radiator. Did you have much less of a problem when the ambient temperatures were cooler?. If so it's time to find a deal on a new radiator.

Roger.

 

If you don't see coolant flowing thru the tubes ( bubbles) with the cap off ( cross-flow rad) . I would think it would be your water pump giving the issues.
My money would be on a water pump.

 

Thanks for the interest and suggestions.
Don't think it's a water pump as I had a timing belt and water pump replaced about a year ago but sometimes new doesn't relate to good.

How can one tell if a clutch fan is bad or good? Mine rotates freely when the engine is off and car is cool, don't know about when it's hotter than hell but I'm about to find out as I'm headed off the hill today, I'll pack enough water for a problem....Tedd

 

Well if it was a head gasket you'd see clouds of smoke coming out of the tailpipe because that causes it to burn coolant (or oil depending on the situation). Here's an example:


You'd also expect to see significant and persistent decreases in your coolant levels. If you haven't seen either of these things then it probably isn't a head gasket.

Someone can correct me if I'm wrong but if the thermostat was stuck closed wouldn't that cause the car to overheat almost right away even during normal driving? If that's so then it's probably not your thermostat either.

 

Stat stuck closed- overheat yes. There a number of ways that a blown head gasket will not drip coolant. Monitor the coolant levels closely.

 

Does it have a secondary electric fan?

 

Yes it could also be a clutch fan or electric fan gone bad if its so equipped? A working clutch fan should tighten up as things get hotter. You should hear it. It should spin no more than 1 to 1.5 revolutions when you try to spin it by hand with engine off and relatively cool. Some like to wear heavy gloves and try to stop it while running. I personally dont suggest that but to each his own. I like all 10 fingers.

 

My vote is on a gunked up radiator or a weak and collapsing lower hose.

 

Well it heated up on the way down the hill twice. I stopped at my mechanic friends place and we did a good going through and he found a crack low in the radiator side wall (plastic radiator). The question is did it cause the problem or is it the result of the overheating. I hate to replace the radiator just to find out that there is a blown gasket or cracked head.

The plan today was to put a temporary JB Weld patch on the split ,let it cure and see if the problem persists. If all is good a new radiator is in order, if not at least I will be able to check the rest of the obvious things with out getting scalded. I should know something tomorrow when the radiator holds water....Tedd

 

I doubt getting hot caused the side tank to split, much more likely it would just puke coolant out of the overflow when pressure got too much. JB weld it if you want, but I think you should save the price of a tube of weld and cut to simply replacing the radiator.
Overheating when cruising but not idling or round town rules out the thermostat, water pump, fan, and gasket trouble. Not many suspects left.....

Roger.

 

Well after a short trip it heated up and reopened the radiator. For some reason at first it will idle for a long time but when put under a load it over heated. It now is showing bubbles at idle. Consensus is she is toast, blown head gasket or cracked head.

It's doubtful I'll drop anymore money in this ride. It's been a good beater but the body is hammered and there are gremlins in the transmission acting up.My thoughts are to let it go to the big pick en pull in the sky and start my search for a new hoopie....Tedd

 

I know you're talking about a 1999 Honda Passport but when I use to work on those Honda's, they have a bleeder screw by or nearby the thermostat housing. When you replace a hose, water pump, draining the coolant, etc, you have to bleed the system. You have to get that air pocket out, if you dont you will overheat. You said repaired the upper and lower radiator hose but did you bleed coolant system?

 

Yep...Tedd