Open Thermostat

My 2000 3.2 rodeo ls temp gauge will not come up to temp. and the idle does not settle down to 850 rpms at idle which makes me believe the rodeo is in open loop and thermostat is stuck open.

I have looked in the Haynes manual (and searched this forum) to see the location of the thermo. and I am left a bit confused. To cut to the chase can anybody tell me the location and procedure to replace the thermostat. If it is easy to access I will do it myself.

John

http://www.automotiveforums.com/vbulletin/showthread.php?t=329383&highlight=thermostat

http://www.automotiveforums.com/vbulletin/showthread.php?t=294544&highlight=thermostat

John, do you have adequate heat from the heater? Just want to rule out a temperature sensor issue. You'd have to go thru the same steps as an IMG replacement as the upper intake has to come off for T-stat replacement. May as well replace the IMG's as well if you have to go in there. Stick with an OEM t-stat. No sense in chancing it with a parts store replacement.
G/luck
Joel

John, do you have adequate heat from the heater? Just want to rule out a temperature sensor issue. You'd have to go thru the same steps as an IMG replacement as the upper intake has to come off for T-stat replacement. May as well replace the IMG's as well if you have to go in there. Stick with an OEM t-stat. No sense in chancing it with a parts store replacement.
G/luck
Joel


Looks like it is going to be a DYI job. If I take it in to the dealer I think I will never be able to walk normally again.

The heater runs lukewarm only.

Just a couple of questions.1) Is the t-stat housing totally concealed by the upper plebum or does it just get in the way?
2) I just had the IMG's done. I think it was only the lower IMG. Do these gaskets self destruct when removing the Intake manifold or upper plebum? Should I order the gaskets just in case.
3) While I have the upper plebum off is there any other maintanences or part exchanges that I should do? The Rodeo is five years old now.

Thanks

John

It's not possible to even get at the thermostat without removing the common chamber/plenum. As far as I know, the IMG's should be ok to reuse. Just give them a look-over before you button the intake back up. You could give the plenum/common chamber a good bath in intake cleaner if you have it out of the truck, but as long as the throttle area & EGR plumbing is clean, I woulnt worry too much about that.
G/luck
Joel

I just got my thermostat. It came with a rubber gasket around the outer perimeter of the thermostat. Is this the only gasket I use or is there suppose to a gasket that goes on the thermostat housing?

John

2000 rodeo

I just got my thermostat. It came with a rubber gasket around the outer perimeter of the thermostat. Is this the only gasket I use or is there suppose to a gasket that goes on the thermostat housing?
o


I called Merlin at St Charles Isuzu and he says the rubber gasket that looks like a small tire is the only gasket you need. On another note my thermostat is stamped with the number 76.5 C . This converts to 169.70 fahrenheit. The 2000 Rodeo v6 only comes with one type of thermostat. So this is not a summer thermostat. Doesn't this sound a little low. Merlin was saying that fuel injected engines usually run from about 180 F to 192 F. Strange.

John

I was looking to replace my thermostat today and I was not sure about some things. So I thought I would walk through it first here on the forum.
The big issue is removing the upper intake manifold. I bought a new gasket just incase there was damage to the old one. So here goes. Correct me if I am wrong. I am moving front to back keeping the throttle body attached to the upper intake manifold

1) purge fuel system by removing fuse and starting car
2) remove negative battery cable
3) remove skid plate and drain coolant from radiator.
4) Remove air intake duct hose
5) Unplug Idle air control valve (IAC)
6) Unplug Throttle position sensor (TPS)
7) Disconnect coolant hoses
8) Disconnect accelerator cable
9) Label and remove vacuum hoses

Haynes mentions something about the disconnecting the transmission linkage from the throttle body assembly. I don't know if this applies to a 2000 Rodeo v6
That should be it for detaching all components from the throttle body
Now heres where I have a problem with the upper intake manifold.

10) remove electrical connectors from the fuel injectors

11) What is the best way to disconnect the fuel lines? The way I see it is that you have to disconnect the hose clamps that attach to the fuel rail then loosen but do not remove on the bolts that secure the rail to the upper intake manifold. Disconnect the fuel rail at each fuel injector, Then there is a device on the drivers side at the back of the engine that I assume is the fuel pressure regulator. It is attached with an allen key bolt. It looks like I can leave the regulator on and just disconect the red electrical connection and two small hoses and one big one.
Please correct me if I am wrong but that is all for the fuel line.

some people would have preform these next precedures first

12) disconnect the map sensor. The Haynes manual mentions disconnecting the power switch and the electronic sensing valve. i don't know exactly what these units are but I am going into this with the theory that I label and disconnect (for easy reassembly) any component that impedes my removal of the upper intake manifold.

13) Remove the brake booster vacuum hose from the back left corner of the upper intake manifold

14) label and disconnect all remaining hoses and there mating parts for easy reassembly.

Now there is this dohickey at the back of the intake manifold that looks like it a spring loaded pivoting arm of some sort. Not a clue if it needs to be removed. I can't see there that well. I could use some reassurance here.

15) unscrew all the upper intake manifold bolts 4 on each side

16) remove upper intake manifold

When I get in there I will access how to remove the thermostat. Meanwhile the only thing different about the assembly from the removal of the upper intake manifold is that you torque down the bolts to 13 ft/lbs in a criss cross manner.

Please chime in and make any corrections.

John

8) Disconnect accelerator cable

I don't think you have to worry about that since you have drive by wire (no cable).

I think this is a great write up!

once you do it, please edit it and post the how to here and I'll put it in the FAQ's!

No Need To Drain Coolant
And It Is Much Easier To Remove The Throttle Body Than To Get At Those Stupid Clamps Holding The Hoses To The T-body
Do Not Disconnect The Fuel Lines You Can Lift And Tie Off The Common Chamber High Enough To Get To The Bolts On The T-stat Housing I Do This Job In About 45 Minutes It Should Not Take You More Than Two Hours
Attempting To Disconnect The Fuel Lines If You Have Never Done It Before On One Of These May Prove To Be A Huge Mistake Do Be Afraid To Ask Questions As You Go

Okay, change of direction. Leave on the fuel lines. Go out and buy some bungy cords and a new throttle body gasket. Yes I see it in my head. The thermostat is at the front of the common chamber. You don't have to raise the common chamber evenly. You can raise the front end higher than the back alllowing you to get better access to the t-stat without having the height of you common chamber lift restricted by the lack of length of the fuel lines. You problably do not have to disconnect some vacuum hoses and electrical connections that you would if you totally removed the common chamber.

My new thermostat has no jiggle pin just a small hole where it is suppose to be. Is this normal?

For the sake of sharing knowledge in the Isuzu community I would love to know all the details of removing the fuel rail connections to the fuel injectors. Something in the back of my head says that you have to replace o-rings once you make the separation.

Tommorrow I will take a mirror to the back of the common chamber and see if that spring loaded dohickey needs to be disconnedted.

Do not mistake my investigations as a sign of a thorough efficient personality. I am doing these investigations because I have become a pussy when it comes to cars. I have a bad history of forcing parts to come apart when things don't make sense. I apprenticed as a tool and die maker. I have dissassembled complicated dies and jigs without any manuals or help. But cars are so quirky it scares the hell out of me.

Thanks for the help. I will get back to you all soon with all the small details.

John

I'm a little confused. Maybe I misunderstood some terminology. I just finished taking apart my throttle body and what I think is my common chamber or upper intake manifold. I don't see how lifting my UIM gets me access to the thermostat housing. Correct me if I am wrong but is not the thermostat housing part of a long metal tube that attachs to a rubber hose on the passenger side of the rad. I can see part of it with a flashlight. The only way I see that I can get to it is to lift up the lower Intake manifold, remove a couple of rad hoses and try to move the wiring harness out of the way and go in there with a couple of ratchet extensions.

So which manifold is which. The uppermost one has one gasket and this one sits on a larger manifold with two separate gaskets. Which one is refered to as the common chamber?

I'll get this right yet.:screwy:

John

the one that the t-body bolts up to is the common chamber = (intake and plenum all in one) do not remove your injectors only disconnect the electrical connectors 1/4in drive ratchet with a 12mm swivel socket will get you down to the bolts so that you can unscrew them without removing the whole common chamber

Well I held off the changing of my thermostat till now because the weather was getting warmer. My tranny was shifting better. So what was the hurry.
The Intake manifold gasket breaks. What happened was I took off the upper manifold before thinking thats all I needed to remove the get at the thermostat. After I saw I needed to lift the lower chamber I left it for later and reassembled the upper manifold to 13 ft lbs torque. What I didn't do was loosen the four nuts on the corners of the lower manifold and retorque them to 13 ft lbs. After a couple of weeks the lower gaskets cracked on three of the four corners. So Friday I took the day off and went at it.
I didn't know which gasket cracked (upper or lower) so I basically went on a exploriatory mission and dismantled everything before I attacked the thermostat.

2000 Isuzu Rodeo LS 3.2 V6

Things you will need to have when you remove intake manifolds, throttle body and fuel rail

- new throttle body gasket
- fuel injector o-ring kit
- upper manifold gasket (1 piece)
- lower manifold gasket (2 pcs.)
- new thermostat

Special tools
- telescoping magnet (hopefully optional)
- hose pliers (optional)
- right angle allen key that needs to be ground down to remove alllen keyed capscrew on fuel regulator between engine and firewall.

Have a table or bench beside the car so you can place parts in a safe and organized manner. Also have separate containers for all bolts and hose clamps.

1) purge fuel system by removing fuse and starting car
2) remove negative battery cable
3) Remove air intake duct hose
4) Unscrew the 4 bolts on the throttle body, then pull back the TB and inspect the gasket. If it is destroyed or stuck on, scrap and clean it off when you reassemble the TB

5) Unbolt the fuel regulator. One allen keyed capscrew is on the side or the drivers side fuel rail. Clearly visible. The other is hidden behind the regulator and the driverside firewall. I never measured the size of allen key needed (someone mentioned 6mm) The allen key needs to be ground down so it will fit between the manifold and the firewall. You have to have the nimble fingers of a magician to make sure you can remove the screw when loosened in order that you don't drop it. If you do drop it it should fall on to the pavement. If not you are going to need the telescoping magnet to retrieve it form its resting place on the bell housing.

6) You are now going to disconnect all relevant hoses and electrical wiring. The logic you must use is to remove anythng that will impede the lifing of the fuel regulator, fuel rail, upper intake manifold and lower intake manifold. (Do not remove both ends of the same hose) All hoses and electrical connects are different lenghts, diameters and connector sizes. So if you don't label them your deductive reasoning and memory should serve you in good sted. If you don't feel comfortable with this, label everything with masking tape and use a numbering system. Start with the fuel injector wiring

7) Now I undid the EGR nut using a 22 mm wrench. Mine had been removed a year ago so it came undone easily. I then undid the EGR electrical connection and undid the two bolts holding the EGR valve. The EGR gasket is metal lined and can be reused. Put the valve to the side and clean it later. (You don't want to do the 22mm EGR nut after you loosen the all the manifold nuts. You won't be able to do it)

8) Undo the hose clamps on fuel hose going to fuel rail. I used a stubby flat headed screwdriver to get a the driverside clamp.All your hoses will be tough to undo because of adhesion due to dryness. The best way to break the bond is not to pull on the hoses but to twist them. This is where the hose pliers come in handy on the bigger diameter hoses.

9) Undo the bolts that hold down the fuel rail and pull the ground cables to the side. With sense of caution lift the fuel rail up until the fuel injectors clear their seat. Now that you have twisted loose the fuel hose and removed the bolts. the fuel rail should be able to be easily pulled out of the fuel hose on each side of the fuel rail. Gas will come out of the fuel rail and spill behind the engine on the bell housing. It will evaporate. NO SMOKING.
Now to lift the fuel rail up and out you are going to have to gently wiggle your way out, slightly spreading the fuel rail apart but not permanently bending it. Do not bang around the bottom of your injectors. Take the fuel rail out and flip it upside down. Look at the four small perforations on the bottom of the fuel injectors. Get those dirty and you are in trouble. Put the fuel rail in a safe clean place with the fuel injector facing the sky. Inspect the o-rings. If one o-ring looks bad, replace all six.

10) I now undid the upper intake manifold bolts and put them in their respective containers according to size. Make sure the two hose connected to the fuel regulator and the upper intake manifold are disconnected. Remove the upper intake manifold and place it on a safe spot where you will not damage or drop it. Inspect the gasket. If damaged replace it upon reassembly.

11) Undo the last four nuts that hold down the lower manifold and place them in their own container or a container that is shared with dissimilar items. Now I used bungy cords to hold up the lower manifold. In hindsight I thing ratcheting straps would have given me more control. Do not put your hooks in the fuel injector ports and do not hook them up in a manner that will damage the mating surfaces.
There should only be two 3/8 diameter hoses still attached to the bottom side of the manifold. I was fed up and didn't want to fight with them to put them back on , I just left the manifold suspended.

I now found the culprit of my manifold leak. Three out of the four corners the gaskets had cracked. I gently removed the gaskets and moved them out of the way of the engine so as not to let any pieces fall into the engine..

11) Vacuum any gasket pieces out of the sides. I also had a lot of sand deposts next to the lower manifold. I vacuumed it up.

12) Take the passenger side hoses out of the throttle body and flip it over to the drivers side. You are going to need more room to remove the thermostat.

13) You are about to remove the thermostat. If you have not drained the coolant you will have some spill on the driveway and puddle in some recesses. I thought I was leaking coolant because of some dripping after all was done. I would recommend draining the fluid if not flushing the system after themostat change

14) There is one rubber hose beside the metal pipe that secures the thermostat. The top part must be removed and pushed out of the way. Remove the hose clamp, twist the hose loose and pull it off. I had a hard time with the clamp so I took it right off and replaced it with a tension hose clamp.
With the tools I had I could only remove 3 out of the 4 bolts that retained the thermostat. At this point I am about to lose it. In the way there is one long 1 inch dia. coolant pipe that goes from the front of the engine to the firewall. I cannot procede without removeing this pipe. I search and find that the pipe is secured with another similar pipe to the back of the engine block. The passengerside bolt is about 1/2 inch long and can be removed. The driverside is about an inch long and should only be removed about 3/4 of a way otherwise you will be assembling it blind. It is difficult , you only have about 2 inches of clearance to deal with. Once these are removed and loosened the interfering metal pipe should move out towards the cabin and clear its o-ring connection letting you bend the pipe out of the way so you can get at the last screw.

14) you will now be able to move the metal pipe up about 4 inchs. Once this is done inspect the position of the old thermostat. Now remove. If you cannot visually inspect the position of the thermostat. Grab it blind remembering the position of your hand. Pull it out and recreate the position of your hand. Thats the position you install the new themostat.

15) If you have drained the system. Spray your thermostat gasket with silicone lubricant. I did not drain the system so I just wet the gasket with coolant and installed it. The reason for this is so the tire like gasket will move into the center position without binding when tightening the four retaining bolts on the thermostat housing. You should tighten each bolt a little at a time in a criss cross pattern. Do not tighten one at at time to full torque. You may clamp it down unevenly and leave a leak. Check the torque settings for these bolts in your manuals. I think the were 18 ft lbs.

16) Re-attach the metal coolant pipe and tighten boltls at back of engine block. I do not see how you can replace the thermostat on a 2000 rodeo without removing this pipe.

17) My EGR pipe in my lower intake was clogged up with only about a 3/32 in hole left. I did not have a pipe cleaner so I just cut a clothes hanger up and chiselled away at the blockage while spraying it full of throttle body cleaner.

18) I now cleaned my mating surfaces up on my lower intake manifold and the engine block. Installed the new gaskets, lowered the manifold in place and put on the 4 outer corner nuts in place, but I did not tighten them.

19) Armed with toothbrush and throttle body cleaner I now cleaned the upper ports on the upper manifold. This took a while but I got them pretty clean.

20) After mating surfaces are cleaned install upper gasket. Put bolts into postion remembering to put on the engine cover bracket. (I forgot and had to remove the fuel rail again after I was finished.

21) Now tighten all manifold bolts and nuts in a gradual crisscross pattern starting from the middle moving to the outside until you torque the bolts down to 13 ft lbs torque.

22) Clean the EGR valve and install. Fasten 22mm EGR nut.

23) After changing fuel injector o-rings, install to fuel hoses. Bolt down the fuel rail remembering to put the grounds back.

24) Attach all hoses and electrical connections

25) Put the throttle body gasket on and bolt down the TB to 8 ft lbs torque.

26) Refill coolant

27) Put the fuel fuse back

28) Hook up battery

29) Start her up and check for leaks

If I miss a step please forgive me.

My Rodeo now gives good heat. Shifts into overdrive imediately. I don't have to wait twenty minutes for the car to reach temp. for it to engage. The engine purrs now and is quieter from the manifold and Egr cleaning.

If you were to just change the thermostat. You probably could just lift the whole manifold and fuel rail assembly and do steps 13 to 16 then skip to 24 to 29.

I am not a mechanic and only offer my experience as pesonal experience. Use at your own risk.


John