Help - Possible bad head gasket?

2000 Rodeo 3.2L. Currently in the tear-down process and have come upon a problem. Bit long winded, but a lot of details to cover: Just under 140K and have had coolant loss and occasional overheat issues for over six months now. Never any boil-overs - always caught it in time, though has hit the "H" mark on a few occasions. Could hear coolant peculating near the heater core (from inside the vehicle) when it was hot. Always had to top off the radiator with two to three cups of 50/50 about every 3-4 days. Morning starts had a stumble and sputter to it for about 30-45 seconds or so before things smoothed out, but never a stall. EGR was cleaned less than 10K miles ago and it wasn't very dirty or clogged. Driven work days approx. 45 miles per day. Never any coolant in the oil and never oil in the coolant that could be detected without forking over dough for an analysis. Had a leak that I thought was under the manifold because I can smell antifreeze after letting the car sit after the drive home from work (mostly highway drive). I figured one of the pipes was leaking under the manifold and thought the overheats were caused by a slow or stuck thermostat (owned it since 64K and have only changed the coolant - never the thermostat). Last Friday on the way home it hit "H" and would not go down. Had not have an over-heat problem in a couple weeks. Pulled over and let it sit. Usually if I quickly goose the throttle to 4K RPM or so it would quickly cool down afterward because of possibly an air pocket was trapped in there. No such luck this time. Soon as it would cool to mid-scale and I started the motor it would creep up to "H" again. Left it and came back later that evening and was able to drive it home with no problem (added about 1/4 gal of 50/50 as it had spewed out the puke tank overflow earlier).

I had stocked up on a bunch of parts months ago so I could get a lot done at once - timing belt/tensioner/idler, water pump, thermostat, all coolant hoses, all coolant gaskets including the two pipe o-rings, complete intake manifold gasket set, injector o-rings, etc, etc.

Got the intake off, timing covers off. No coolant under the intake... Perhaps it evaporated overnight? Got the thermostat out and put in in a pan of water over the camp stove along with the new thermostat. Watched and stirred while monitoring the thermometer. As it came to temperature the thermostats started to open - both of them. The plot thickens. Why the overheat? Why the stumble in the morning? Why the coolant smell?

Started to pull the plugs one by one. All were looking normal (light gray) and have a tad over 20K on them since I last changed them. Got to #5 cylinder and the plug was a bit cleaner than the other five. One side of the insulator was white - like brand new white. Is that the tell-tale sign of a leaking head gasket?

I would like some experienced opinion before I pull the head and automatically lose $100 in a head gasket and bolts. I am thinking about doing a compression test to see what #5 is doing compared to the others. Shining a light down the spark plug hole I see a black piston top. If the plug is clean, would not the top of the piston be somewhat clean? Piston top looks fairly black with carbon deposits - no metal visible.

Say the compression test is fine - all within 10-15% and disregard the cleaner plug, what could explain the overheat when the water pump and thermostat both work? Radiator has a good 1/3 or so fins bent over from car wash high-pressure water (don't ask), but that has been like that for much longer than this overheat problem. Any ideas?

It could be a cracked head and that one plug is getting a good steam cleaning.

One more bit of info: After pulling over due to "H" condition, the upper radiator hose was scalding hot and stiff while the lower was no where near as hot.

With thermostat verified as working, would one agree the radiator could be clogged? I plan to run the garden hose on it later this evening to verify.

Hope the head is not cracked! What does a rebuilt/new head cost for the 3.2L DOHC?

Update: Ran garden hose full-bore through radiator - flows fine, no problems. Any ideas guys? Hearing crickets...

I remember about a year ago when someone had a problem similar to the one you are experiencing. He posted the symptoms, hung around here for a short time, then disappeared. We never heard if he was able to resolve the problem. That's the downside of any forum.

I thought you may have cornered the overheating trouble with the radiator diagnosis, I'm scratching my head right now....

Sorry about the crickets.


Good Luck,
Dale

2000 Rodeo 3.2L. Currently in the tear-down process and have come upon a problem. Bit long winded, but a lot of details to cover: Just under 140K and have had coolant loss and occasional overheat issues for over six months now. Never any boil-overs - always caught it in time, though has hit the "H" mark on a few occasions. Could hear coolant peculating near the heater core (from inside the vehicle) when it was hot. Always had to top off the radiator with two to three cups of 50/50 about every 3-4 days. Morning starts had a stumble and sputter to it for about 30-45 seconds or so before things smoothed out, but never a stall. EGR was cleaned less than 10K miles ago and it wasn't very dirty or clogged. Driven work days approx. 45 miles per day. Never any coolant in the oil and never oil in the coolant that could be detected without forking over dough for an analysis. Had a leak that I thought was under the manifold because I can smell antifreeze after letting the car sit after the drive home from work (mostly highway drive). I figured one of the pipes was leaking under the manifold and thought the overheats were caused by a slow or stuck thermostat (owned it since 64K and have only changed the coolant - never the thermostat). Last Friday on the way home it hit "H" and would not go down. Had not have an over-heat problem in a couple weeks. Pulled over and let it sit. Usually if I quickly goose the throttle to 4K RPM or so it would quickly cool down afterward because of possibly an air pocket was trapped in there. No such luck this time. Soon as it would cool to mid-scale and I started the motor it would creep up to "H" again. Left it and came back later that evening and was able to drive it home with no problem (added about 1/4 gal of 50/50 as it had spewed out the puke tank overflow earlier).

I had stocked up on a bunch of parts months ago so I could get a lot done at once - timing belt/tensioner/idler, water pump, thermostat, all coolant hoses, all coolant gaskets including the two pipe o-rings, complete intake manifold gasket set, injector o-rings, etc, etc.

Got the intake off, timing covers off. No coolant under the intake... Perhaps it evaporated overnight? Got the thermostat out and put in in a pan of water over the camp stove along with the new thermostat. Watched and stirred while monitoring the thermometer. As it came to temperature the thermostats started to open - both of them. The plot thickens. Why the overheat? Why the stumble in the morning? Why the coolant smell?

Started to pull the plugs one by one. All were looking normal (light gray) and have a tad over 20K on them since I last changed them. Got to #5 cylinder and the plug was a bit cleaner than the other five. One side of the insulator was white - like brand new white. Is that the tell-tale sign of a leaking head gasket?

I would like some experienced opinion before I pull the head and automatically lose $100 in a head gasket and bolts. I am thinking about doing a compression test to see what #5 is doing compared to the others. Shining a light down the spark plug hole I see a black piston top. If the plug is clean, would not the top of the piston be somewhat clean? Piston top looks fairly black with carbon deposits - no metal visible.

Say the compression test is fine - all within 10-15% and disregard the cleaner plug, what could explain the overheat when the water pump and thermostat both work? Radiator has a good 1/3 or so fins bent over from car wash high-pressure water (don't ask), but that has been like that for much longer than this overheat problem. Any ideas?


If one plug is notably lighter than the others, i would suggest a crack or a gasket leak somewhere. Very possibly running lean on that 5th cylinder.

I know the carbon buildup doesn't seem likely to be running lean but that's what the plug indicates.

Flush all the coolant out of the engine, hook a hose up to the bottom most hose and pump away until it runs clear it might just be gunked up from mixing coolant types?

If compression test came back with #5 an average as the other cylinders I'm not sure what to tell you.

sounds like its sucking in coolant and burning it off 'my car does this and isn't a concern so long as it continues to BURN what is brought in' if it stops burning what coolant it brings in then you run the risk of hydroshock and rust occurring.
id say this to GM:flipa:

One more bit of info: After pulling over due to "H" condition, the upper radiator hose was scalding hot and stiff while the lower was no where near as hot.

With thermostat verified as working, would one agree the radiator could be clogged? I plan to run the garden hose on it later this evening to verify.

Hope the head is not cracked! What does a rebuilt/new head cost for the 3.2L DOHC?

Update: Ran garden hose full-bore through radiator - flows fine, no problems. Any ideas guys? Hearing crickets...


your looking into the 100's$ for a new head and about the same for a used unless you can find someone to weld it up and such, you'll likely loose power but as far as that goes having less power and a vehicle to drive is worth it in my eyes.

Very possible that your radiator is clogged.

It could be a cracked head and that one plug is getting a good steam cleaning.


as what i thought until i remembered he said the pressure's were almost all green across the board meaning that the #5 cylinder isn't loosing pressure due to sucking in or pushing out water...:sly:

Some pics:

#5 plug (clean on one side):
http://www.theschwalls.info/uploads/num5plug-50.jpg http://www.theschwalls.info/uploads/num5plug-os-50.jpg http://www.theschwalls.info/uploads/num5plug-fr-50.jpg


#2 plug (general condition of remaining plugs): Also all plugs had a slight green tinge to them
http://www.theschwalls.info/uploads/num2plug-50.jpg http://www.theschwalls.info/uploads/num2plug-os-50.jpg

These plugs have about 20K miles on them. Have not done a compression test yet - debating if it will tell me anything with the engine cold. Engine presently torn down (no intake) and am unable to bring it up to temperature for a valid test. Probably will do it regardless. I ordered the right head gasket and eight bolts from hondapartsnow.com ($25 cheaper than st. charles, but still $101 shipped :frown: ) so I bit the bullet on pulling the passenger-side cylinder head.

http://www.theschwalls.info/uploads/engine-50.jpg

More info:

Installed the old timing belt and pulled the fuses for the fuel pump and ECM to do a compression check.

Engine cold and cylinders dry:

1: 88
2: 150
3: 165
4: 60
5: 180
6: 135

My day gets worse and worse. #1 & 4 I verified three times - all within 5 psi of each other. #5 was the suspect gasket/crack cylinder and it has the highest compression! I verified the engine timing twice. Rotate crank till #2 at TDC and marks line up at 3'oclock on the crank cog and oil cover. Right bank rotate until it detents to the mark on the cover. Left bank rotate until the cog detents on the mark at 9 o'clock then rotate another 1/4 turn or so to line up with the mark on the cover. Install belt. Old belt had the dotted line worn off so I may have been a tooth off on the crank, but I don't see a connection with the low compression on 1 & 4 without seeing an engine model in rotation. Any timing gurus out there?

-Posting on plantisuzoo as well due to low traffic/replies

Did leak-down test:

1: 50% - leaking at intake valves: flushed with tool oil, but still leaking at the seat, more so on one than the other and right between them
2: 35%
3: 32%
4: 53% - Air came out #2 plug hole. Installed #2 plug and air leak stopped. Still same percentage, air sound faint in exhaust
5: 25%
6: 40% - leaking at intake valves

Pulled both valve covers. That last bolt on the left bank near the brake booster is a PITA! No obvious problems. Some cam lobes have an interesting stain on them compared to the others that are clean metal. Will post a pic tomorrow. Any ideas - pull the heads?

bump