01 Rodeo Overheating - Opinions?


Shore_Fisher
10-12-2010, 01:45 PM
I have read a lot now about overheating problems on the Rodeo, and I have the same issue. I'm looking for some opinions on likely solutions to my 2001 V6 w/156 k miles.

Problem came to my notice about 1 year and 15 k miles ago when I was idling the vehicle when parked to charge up my battery (A whole other issue...). I left it for about 30 minutes and came out to a steam gusher. Radiator header was melted, radiator lined with some sort of white coating, not nice... But to my surprise, once I let it cool off, replaced the header, changed out the oil and refilled the coolant, it seemed to run fine. The oil was very gunky, and it took me two or 3 early oil changes to get it clear again, but there was no water in the oil.

Since then I have had to keep topping up the coolant at regular intervals (I admit, I've been using tap water mainly. But I've changed my ways now, honest). I thought this was because the plastic bracket from the top of the radiator to the header tank pipe had been damaged during the overheat and was letting out some coolant each time I ran it, but there never was enough of a leak to drip/pool under the vehicle. But I have also noticed that some times when I have run the vehicle for a while (I'm talking 20 miles in town) there is a slight hissing sound from the engine bay when I shut down. This is gas coming from the header tank overflow.

I went on a longer trip recently, and ~100 miles out into a hilly region - Bang! - Off pops my header tank lid and steam/coolant is gushing out. Let it cool down and re-filled coolant, but same thing happened another 10 miles on. Two things that may be significant: The lower rad hose appeared to be empty and not too hot, even after refilling and running the engine to temp; and there was rapid bubbling of gas out of the header tank valve thing. This seemed to be sort of engine-speed related, but it also continued quite a while after I shut the engine down, so maybe it was just steam bubbling out...

Oddly, the temperature gauge never went above the middle until AFTER the header tank lid had popped off. Gave up on the trip and limped back home slowly without another pop - although there was the familiar hissing when I shut down, and I was about half empty on coolant again (Temp gauge normal all the way back). I have never seen any signs of oil in the coolant (And I have drained/filled this a lot of times now!)

Subsequently I have replaced the thermostat (Cleaning out the significant gunk in the intake in the process), to no noticeable effect, removed the water pump (Looks good to me) and am planning to replace all timing belt/pulleys, water pump and radiator next (Even though I ran a hose through the rad and water seemed to flow OK).

So, on to some questions:
- Do I have a blown head gasket?
- If so, is it worth fixing (machining heads/block), or do I go for a new engine?
- The radiator is the problem isn't it?
- Could a partially blocked radiator prevent ANY flow through the lower hose?
- How do I check the fan clutch? (This may have been my initial cooling problem)
- Why does my gauge not show I'm running hot?

Probably lots more questions, but I'm ready to learn some stuff from you experts now!

Ed

amigo-2k
10-12-2010, 02:15 PM
Typically if you change the thermostat and nothing happened the Rad is the next logical thing.

I've read plenty of posts, were people flush, change the thermostat, change the water pump and that didn't help. Change the rad... and all is well .....

Shore_Fisher
10-25-2010, 11:46 PM
So, changed the thermostat - No difference; Changed the water pump and radiator (With the timing belt, pulleys, etc, etc, at the same time) - No difference. Flushed system (As I wasn't sure I had got all of the old fluid/crap out) and re-filled with 50/50 coolant/distilled water - No difference.

Actually, there was a small change - The engine seems to run with one or two cylinders missing for a few seconds after I start it. But it idles fine, runs good - Just gradually looses coolant and temperatures start fluctuating wildly if I let the level get down too far.

I have been religiously checking the oil for water on the dip stick and seeing nothing, but I looked a little closer into the rocker covers and I can see some whitish gunk in there which I take to be coolant in the oil. Is it normal to not see evidence of water on the stick, or when the oil is changed?

Anyway, I'm now running to work and back and adding about a pint of coolant a day. Temperature is rock-steady near the middle of the gauge if I keep it well topped off. I'm now planning the next steps. Would appreciate any thoughts on likelihood of being able to fix with just a head gasket change? Or is it more likely that I have warped/cracked something?

Any comments appreciated. And any checks I can make to help diagnose would be really welcomed.

Ed

amigo-2k
10-26-2010, 07:03 PM
you may want to send a sample of your oil in to see if anti-freeze is in the oil.

http://www.blackstone-labs.com/

Shore_Fisher
11-23-2010, 12:48 PM
OK, so I've been running for a few weeks with topping up the coolant every 20 miles or so (Gets me to work at least!) and now I'm going for the big fix. I'm pretty certain my problem is exhaust gases going into the coolant that are pushing out coolant from the expansion tank, leading to low coolant levels and overheating. There is also some coolant getting into at least one cylinder, at least when it is cold.

I'm hoping that I can fix this by just replacing the head gaskets, so I'm going to get a head gasket set and pull it apart over the holiday. I have read that quite a few people seem to snap head screws when taking these engines apart. Are there any tips on preventing this? (Impact wrench, penetrant, heat, etc).

My plan is to do a compression check on each cylinder, then (hopefully) just replace one head gasket. I would love to do both, get the heads pressure checked, skimmed and regrind the valves, etc while I have it apart, but I cannot get that done in the time I have right now. I'll look over the head/block for obvious cracks or damage when I clean them up, and rethink the plan if I see something nasty, but I'm hoping this will fix, or at least improve, my immediate problem.

So, any advice on the head screws? And any other recommendations?

1999passport
07-27-2011, 11:00 AM
hey shore_fisher i have the same problem with my passport. did you ever fix the overheating problem, was looking at your last post on 11/11/10 and did not see the ending. i don't see any other foums with this same overheating problem.

Shore_Fisher
08-08-2011, 12:01 AM
So I did fix my problem. As planned I bought a pressure gauge and measured each cylinder in turn. No significant difference between each of the cylinders, and all near the correct range, but the passenger side bank rear-most cyclinder (Whatever number that one is) shot a bunch of water out of the spark plug hole when I first cranked it, so I knew where my coolant was going. But I was still a little surprised I had good compression with what I thought was a well blown head gasket around that cyclinder.

I had my head gasket set, new screws and the various other bits and bobs recommended to be changed for that level of teardown, and I located a local shop who could clean and test the head once I got it off. I planned on a machining of the head surface, with just a clean-up of the block surface and new gaskets, as I didn't want to go any further on the teardown (In case the problem was deeper, and a new engine was the solution).

I can tell you one thing - that those head screws are TIGHT after a few years of being in place. I tried applying some heat to the block near the threads, but I was a little worried about distorting the block, so I'm not sure if it did any good or not. Sprayed everything with penetrant, but there is really not anyway I can see that it can get to the threads. Anyway, with a brand new Allen bit and a looong breaker bar, I braced against the engine bay and cracked those babies off! (In the recommended order, of course) All except the obligatory one, which just would not start, and I rounded out the drive element.

Looking at the screws I'd already removed, and the holes in the head, I reckoned that there was enough room to drill the head off without touching the head itself, so I selected the appropriate drill bit, masked off well with aluminum duct tape and towels and went for it. Screw head eventually popped off with a zing! Now I could take the the head off (Not as easy as it sounds with a 6" screw shank to clear), and the problematic screw shank actually unscrewed by hand.

With the head off, I couldn't see any obvious leak path near the problematic cylinder, but I sent the head down to the shop and got down to cleaning up the block. After much reviewing of acceptable levels of cleanliness and surface finish for head gasket surfaces, I did what I could to clean up the block. I needed to use a razor edge on (very carefully!) to get a few bits of crud off, but mostly I used pastic scouring pads and lots of chemicals. Buffed up the pistons crowns a little while I was there, and all looked good.

The shop got back to me after cleaning the head, and let me know I had a crack in the head. I went down and looked and right enough, you could see a long crack in the casting on the top side of the head, running from the problematic cylinder exhaust valve a good 3 or 4 inches along the surface of the casting. I would say that you would have had little chance of seeing this with the head in place in the car. This explained the good compression, and the fact that the car was running well, except for loosing coolant - I was obviously leaking coolant into the exhaust at this cylinder, with exhaust gases also going into the coolant galleries, giving me all sorts of nasty air locks and the like.

Anyway, no chance of a repair, as the crack went way off into some deep, dark corner of the casting, so I located a reasonably cheap reconditioned head shop and got a new one. I was a little surprised that I had to swap everything down to the inlet and exhaust manifold studs from the old head to the new one, but eventually I got that thing fitted, adjusted eveything up as I read on here (Timing worked first time!), and she runs good.

So I'm pretty confident that my original problem was the cracked head, which got progressively worse as I repeatedly overheated due to continuing loss of coolant. Frankly, having read what I have here about the susceptibility of this engine to damage due to overheat, I am surprised that the repairs I did got me back to a seemingly normal (For the mileage) running car, but maybe my idea of overheating is different to other peoples.

Tips? First, take the cams off while the head is still in the car if you are going to do it anyway, as it helps get the head screw driver bit on nice and square. If you do not want to, then rotate the cams to align the flat spots to allow you to get best access to the screw heads. Clean those heads out with chemicals, air, brushes - everything to give you the best engagement you can. And use a new bit.

Second, don't be afraid to use the starter to break the crankshaft pulley nut off. I was worried, and spent a couple of nights working on tooling to allow me to get it off, to no avail. Once I got annoyed enough to try what I had read about on the Web, I found it works quite well. First, make sure you know what way the engine runs! Remove the fuel pump, ignition, etc fuzes, pull out the plugs and leads, remove the injector plugs - Basically everything you can think off to prevent the engine from possibly starting. Put your socket and wrench and breaker bar on the screw head, brace the breaker bar against the engine bay wall with a good amount of wood, carpet, whatever. Turn the engine by hand so that the breaker bar is already pushing hard against the wood, then turn the key. Briefly. Eveything will fall off, but the screw will be loose.

Questions? Why does the temperature gage not show ANY increase in temperature before the system boils over?

Ed

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