98 Rodeo Overheating & Leaking Coolant

02-07-2010, 10:07 AM
This is my first post here. I've visited for months reading and learning. I have a problem that I just can't figure out. Wednesday, after driving down the interstate for 45 min, I parked my truck at work. Once in park I noticed steam barreling from under the hood and heard a hissing noise. I popped the hood and saw that it was coming from the intake manifold area. That afternoon I started it up and let it run for a few minutes in park. No problem. I turned the heater on to see if it would blow hot air as I drove. I made it maybe 10 minutes down the interstate before I had to pull off. It went from cold to near the red on the temp gauge and the heater never blew hot air.

We towed it to my shop and I thought it was either the water pump or the thermostat. When it over heated the second time the upper radiator hose was very hot. I didn't think to check the lower. So here is what I did:

1st attempt
I took everything off down to the timing belt (as far as I could get, see image below). The pump looked clean, although I couldn't see the weep hole on the bottom side. The coolant was in the "V" below the lower intake manifold which made me think thermostat since that is where it is.

http://www.alatrails.com/photos/albums/userpics/10391/engine.jpg (http://www.alatrails.com/photos/albums/userpics/10391/engine.jpg)

2nd attempt
I took off the upper and lower intake manifold. There was about 1/2 gallon of coolant sitting in the "V" below. I removed the thermostat and replaced it with a Duralast from Auto Zone. It didn't really look the same as the OEM that I took out. It was shorter and didn't have flanges on the sides to sturdy it up. I made sure to replace it in the same position as the one I removed. I put everything together. Filled up the coolant, and started it up.

It roared at first, but quieted down after about 30 seconds. It was idling around 1000 RPM (high I know). No leaks at first. The temp hand never moved. I felt the intake around 2 minutes and no heat, the left bank was hot though. No heat in upper or lower radiator hose. That made me nervous after 3 minutes so I shut it down.

When I did, same story as when all this stared. Steam from around the manifold. Leaking coolant dripping from under truck, couldn't tell where it was coming from. Likely running down. I think there was coolant back in the "V" area. I also noticed some liquid on the ground from the exhaust.

1. How do you relieve the tension on the serpentine belt tensioner?
2. How do you remove the crankshaft pulley?
3. What do the symptoms sound like to you?

Any help would be greatly appreciated.

02-07-2010, 03:23 PM
1.Put on a socket wrench and a pipe and give a pull


3. There are a couple of hoses under the intake manifold that I think have 0-rings. Typically these will last about 150k.... couple of posts on it below:




02-07-2010, 04:29 PM

Great! Thanks for the info. I had read the tensioner loosen technique in the Haynes manual, but didn't think it made any sense. I guess I'll give it a shot if I have to get into the timing belt or the water pump.

If my issue is the O Ring illustrated from the above post, that would be great! That is easy to get to without removing the IM. I'll give it a shot and post back. The only question I have is, if it is an O ring, wouldn't the thermostat still allow enough hot coolant to move through the upper radiator hose to warm it up?

http://img.photobucket.com/albums/v260/dae_amp_ika_dtp/rodeo/1newo-ringinstalled.jpg (http://img.photobucket.com/albums/v260/dae_amp_ika_dtp/rodeo/1newo-ringinstalled.jpg)

02-07-2010, 09:27 PM
I just checked the old thermostat and it was good. That wasn't the problem to begin with. I hope this O Ring is the culprit. I'll check that out tomorrow.

02-10-2010, 08:21 AM
I have it broke back down. The area where the O Ring is looks pretty good. I'm going to replace all hoses and O rings while I'm there though. While I'm replacing the water pump, I've read that it is recommended to replace the tensioner pulley, idler pulley and the timing belt. Which tensioner pulley is being recommended, the timing belt tensioner or the serpentine tensioner? Also, I still can't see how to get the serpentine tensioner off. Anyone know?

02-10-2010, 09:03 AM
Timing belt tensioner (referred to in manuals as "Pusher") is the one normally recommended for replacement whenever timing belt it replaced. Costs about $90, I think.

Serp belt tensioner is attached (if memory serves me) by two long bolts that attach the tensioner assembly to a large metal bracket located right above the alternator. Bolts are to left of tensioner pulley, as I recall. You can't see the lower bolt, only feel it below the spring holder of the tensioner assembly. Mine was not bad & still using the original at 140K mi.

CORRECTION: While checking the oil last night, I took a close look at the serp belt tensioner and it is secured with an internal hex bolt through the center of the spring housing, as well as a regular bolt just to the upper left of the spring housing. Sorry, my poor memory.

One word of caution (in hopes you won't make same mistake I did): before you remove timing belt, be sure & rotate the engine (by slowly turning the crank bolt clockwise facing engine) so that the notches/blue marks on both cam pulleys line up with the marks on the heads. Then, DONT MOVE either the cam pulleys or the crank during the work. Reinstall of new timing belt will be a lot easier. I was too dumb to do that my first time, so ended up completely tearing the thing back apart after install of the new timing belt cause I was a tooth off on one of the cam pulleys. Good on other pulley & crank. It ran, but very poorly.

BTW, I tried to reuse the O-rings on the coolant pipes up high, that insert into that funky coolant manifold thingy. Bad idea. After I got the timing belt installed the SECOND TIME, and got the engine running good and it warmed up, coolant started running all over everything! Finally figgered out it was coming out of the large O ring. Those suckers are kind of hard to find, so I simply cleaned up/reinstalled the old O rings, but coated them liberally with RTV on reinstall. Guess I got lucky cause the leak stopped. Still havent replaced the original O rings and the timing belt job was done at 95K.

I added a pic of mine with the serp tensioner bolt hole locations & timing belt pusher pointed out. Hope this helps.

02-13-2010, 08:31 PM
I just finished putting everything together and now I have new problems!

First let me detail what I did:
1. Removed upper & lower intake manifold. Degreased. Replaced gaskets.
2. Replaced all coolant hoses, fittings, & O Rings under the manifold.
3. Replaced thermostat (although old one was good).
4. Replaced Timing Belt & tensioner.
* I removed 4 of the plugs to relieve the compression on the pulleys.
* Had to replace one plug as I broke it. Used NGK. Set all gaps at .042.
* Right bank camshaft pulley was slightly misaligned with the mark on the block after removing the old timing belt. I rotated it about 2 full rotations until it sprang into line with the mark. The left bank pulley stayed in line the whole time. I'm not sure about the crankshaft pulley. I think the keyway was at the 3 O-clock position, but not certain. Once the belt was on, I didn't rotate the syetem to make sure everything was on it's mark.
5. Replaced water pump & gasket (although old one looked ok).
* I made sure to use loctite on the correct water pump bolt.

The coolant is now flowing correctly. No overheating, leaking, and heater is working fine.

The new problems:
1. It is backfiring and it smells like it is running rich (strong gas smell in the exhaust).
2. High idle 1500-1000 RPM.
3. Metallic chattering when in drive or reverse.
4. No power in drive and even less in reverse. I had to get a running-go just to get back in the garage and it is level terrain!
5. Check engine light is on but I don't know the code yet.

I've read around and it sounds like it's out of time. Based on my description of how I replaced the belt, what do you think? Any other areas to look at? Timing wouldn't cause it run rich would it?

02-13-2010, 08:58 PM
Man, I hate to say it, but unless the machine was running like this before you started this whole process, I would guess you got it mis-timed when you installed the new timing belt. Easy to do. I sure did it.

Sorry, but I think you are gonna at least have to remove the plastic covers over the cam pulleys, and remove the crank pulley so you can see how the notches line up with the belt marks. I'm betting they will be off a tooth or two somewhere. Mine did the same thing when I reassembled it mis-timed. It, too, ran rich & smelled like heck. It's missing cause it's mis-timed, pumping gas into the muffler, which is why it's backfiring.

That's my guess, anyhow. Sorry, & good luck.

02-13-2010, 09:33 PM
That's what I suspect too. I wasn't sure it would cause the backfire though. Oh, well. I'll have to break it back down. I have re-done the IM twice so I guess it's par to do the timing twice. ;).

02-14-2010, 04:07 PM
That was it. I had the timing wrong. It was pretty easy to correct. I had missed the crankshaft pulley notch with the mark on the oil pump by a tooth & the left bank camshaft pulley was way out of time. I had turned the LBCP until it snapped into line with the mark on the block. That is wrong. You are supposed to turn it until it snaps to the hole at the 9 O Clock position and then turn forward about a quarter turn until it lines up with the mark on the block. I reassembled and turned it through a few rotations to make sure the marks hit right and they did. I've been driving around all day and my Rodeo is running like a charm. Thanks for all the helpful input everyone. I have a civic to work on now. :)

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