Mechanics

REPLACING THERMOSTAT

1998 Honda Passport

Engine Cooling problem
1998 Honda Passport 6 cyl Four Wheel Drive Automatic 222229 miles

I need to replace the Thermostat. Where can I find an exploded view of the intake manifold plenum, coolent tubes and Thermostat? I need to see what I need to remove to get to the thermostat and it's buried under a lot of stuff. I looked at Haynes Repair Manual but what they show can't be right for my model. I have a V6-3.2L engine (RLV type). These cars are essentially ISUZUs with Honda Logos as you know.
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Markieji
September 22, 2009.



Removal & Installation of thermostat

Disconnect the negative battery cable.
Drain engine coolant from the radiator and engine.
Disconnect radiator hose from the inlet pipe.
Remove the thermostat housing, then remove the thermostat (2)


http://www.2carpros.com/forum/automotive_pictures/46384_thermosta_1.jpg



To install:

Install the thermostat into the outlet pipe (4) making sure that the air hole is in the up position.
Install thermostat housing and tighten the bolts to 18 ft. lbs. (25 Nm).
Attach the radiator hose to the inlet pipe.
Refill the engine with the proper type and amount of coolant.
Connect the negative battery cable.
Start engine and check for coolant leakage.

This may help, if not let me know:

Tiny
Mathiaso
Sep 22, 2009.
This is very helpful, thank you. But, my immediate concern and question is the process of actually getting to the thermostat housing. It's under a lot of other things that I need to remove. I was hoping for an exploded view of the things I need to remove to actually get to the thermostat housing. I was told that I had to remove the intake manifold plenum ... how do I do that?

Here is a picture of what I am dealing with. The Thermostat housing is buried under a lot of stuff.

An exploded view like the one you provided for the thermostat housing is what I am hoping for. Thank you.


http://www.2carpros.com/forum/automotive_pictures/412531_400s_1.jpg


Tiny
Markieji
Sep 22, 2009.
Can you see the big hose from the air filter from the picture you sent me?
It is attached with clamp on throttle body.
Above the belt there is a hose from the radiator upper part( radiator uper hose)drain radiator before removing it.
The inlet under the big hose from the air filter have bolt, attach to the engine block.
Remove the bolt and the thermostat is right there.

Let me know

Tiny
Mathiaso
Sep 23, 2009.
I have the same problem. It appears to get to the thermostat you have to remove the intake manifold. I tried doing it without removing the intake manifold but was unable to get to the back bolts. The wiring harness is blocking access from the front, and the manifold blocks access from the top. Anybody have any idea for the 1998-2002 Honda Passport thermostat?

Tiny
Mganders
Oct 2, 2009.
I'm not very satisfied with the information I've gotten so far. I even subscribed to the " on-line" manual that is being promoted here I think it's " Mitchell1 eAutoRepair" . It was worthless for this repair. Haynes manual provided mis-information. So, I'm about to plunk down the $50-60 for the Manufacturer's Repair Manual to see if that's any better. Please let me know if you get the info on how to do this. Thanks

Tiny
Markieji
Oct 2, 2009.
So turns out you do have to remove the intake manifold. Crazy! What a horrible design. I found a number of sites that confirm this is the case. Here is one.
http://www.2carpros.com/topics/cooling-system/thermostat

This site has some great FAQs about the Passport(Rodeo)
http://www.isuzufaq.com/

They have a section in there that explains how to remove the intake manifold. Doesnt sound too bad but what a pain just for a thermostat!

I wasted the money on the shop manual as well. Doesnt even show our engine. The engine in that manual is the pre 1998 V6 I think.

Im starting to think its not worth my while and am tempted to see how much a Honda shop would charge. Im guessing in the hundreds, but maybe worth not spending two days working on the thing.

Good luck. I will let you know what I do.

Tiny
Mganders
Oct 2, 2009.
By the way. If you do decide to do this I was told to use an OEM thermostat, and to absolutely make sure to replace the intake manifold gasket.

Tiny
Mganders
Oct 2, 2009.


http://www.2carpros.com/forum/automotive_pictures/46384_new_1.jpg



you need extension to gewt inn there underneath to get the bolts before getting the thermostat out.

Tiny
Mathiaso
Oct 2, 2009.
That is exactly what I hoped as well. But to no avail unfortunately. Even with my 12mm swivel ball socket I could not get to the back bolts. There is just not enough room. I gave up when I realized that even if I did manage to get the bolts loose that getting it out and back in with the new thermostat would be an even bigger feat. But maybe I am missing something.

Tiny
Mganders
Oct 2, 2009.
The quote I got from the dealer was $260 to replace the thermostat. My local repair guy (whom I like) quoted $290! So, that tells you it's a job to replace them.

Mathiaso -- I DID remove the hoses and connections you show in the photo. But the actual thermostat housing is not revealed. Its much deeper under the intake manifold. So I guess the question now is: what is the procedure for removing the intake manifold.

Mganders -- thank you for the leads to additional information.

Tiny
Markieji
Oct 3, 2009.
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