Author Topic: Coolant Problem - What's Next???  (Read 6939 times)

PilotSniper

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Coolant Problem - What's Next???
« on: November 28, 2005, 09:16:30 PM »
Okay guys, here's a doozie I really need help with...

Once apon a time, I wanted to get my Pilot back up and running after my lower back fiasco, so I decided to get a couple of things fixed and some maintenance done. I had a problem with my reserve fuel sensor, which wasn't working, and another problem with leaking coolant, so I figured I'd tackle these problems head-on.

Regarding the reserve fuel sensor, I ordered a replacement sensor. No big deal.

Regarding the leaking coolant, I looked under the Pilot with the engine cranked and saw that I had a shot mechanical seal (leaking coolant profusely through the cheater hole under the water pump) which, I believe, was caused by a kinked radiator hose that was going to the head. The hose used to curve nicely into the top of the head, but with time, it developed a kink which I believe caused the coolant to stop flowing, which, in turn, caused the mechanical seal to overheat and crack in two places. Since I was changing hoses and getting deep into the whole cooling system, I decided to change out the radiator cap, too. It was looking rather ragged after all of these years of use.

The rebuild began with the removal of the fuel tank. Not only was the reserve fuel sensor shot, but I noticed that there was a small amount of surface rust inside the fuel tank. I took some washers and dumped them into the fuel tank, along with some POR-15 metal ready conditioner in order to remedy the surface rust situation. The tank came out great, so I changed out the bad sensor for the good one and completed the task at hand.

Next, I had to tackle the right side cover in order to change out the mechanical seal. Not only did I change out the mechanical seal, but I put a new water pump shaft in as well. Call it preventative maintenance or whatever you like, but it helps me sleep at night.

Either way, I put everything back together and decided to do some maintenance work. Not only did the right side get new oil, but the case got an oil change as well.

Here I was, all done with everything I set out to do, but things didn't work out as good as I had hoped. On the maiden voyage out, my engine quit 30 feet from the house. Fortunately, the culprit was a defective spark plug and a new one cured the illness.

Next, since I had cleaned out the tank, the two subsequent fuel tank flushes apparently weren't enough. A few little (and I mean little) rust particles were enough to cause my carburetor's overflow tubes to go into fuel overflow during my second test run. Fortunately, a thorough cleaning of my carburetor's float bowl was all she needed to squash that issue.

Lastly, this is the problem I need help with. I fill the radiator with coolant to the top, purge the air by throttling the engine, then top off with coolant again. If I take her out for a hard run, she'll start to overheat only a few minutes into the run. When the Digatron yells at me, I shut her down and take a peek into the radiator. By this time, it's usually half empty. The only leak point is the pressure relief hole built in to the radiator cap. This is only supposed to spew when the cooling system reaches 20psi. To test this, I put a gauge onto the small radiator hose that used to carry coolant through the OEM carburetor's heating system. I pressurize the system to 15psi without any leakage of pressure. As soon as I hit 20psi, the pressure relief hole in the cap does what it's supposed to do and spews coolant.

After the repair of the mechanical seal, I have a beautiful stream of coolant flowing through the cooling system. If you peek into the neck of the radiator, you can see the coolant flow coming back in from the head's return hose.

After the pressure test, I have concluded that I don't have any leaks in the cooling system. I have also concluded that the radiator cap is working as per the manual's specifications.

I have checked and rechecked all the hoses and can certify that there are no hoses that are kinked or pinched in any way.

I have flushed the radiator with a garden hose from the top to the bottom and I don't have any obstructions in the radiator.

I have flushed the entire cooling system via the bottom radiator hose with the garden hose, causing fresh water to flow through the entire cooling system (minus the radiator) and it comes through successfully, which indicates that there are no obstructions in the cooling system.

Why, then, when my engine heats up during a hard ride, does the pressure of the water exceed 20psi and cause the radiator cap to go into "pressure protection mode" and spew coolant not only into the reserve tank, but out through the cap's hole?

Has anyone ever encountered this problem and what do I do to remedy the problem?

Can anyone think of something that I haven't tried yet?

As you might imagine, this one is really kicking my ass!

Thank you in advance for your help!!!
I started out with nothing and I still have most of it left!  :shock:

PilotHawK

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Coolant Problem - What's Next???
« Reply #1 on: November 28, 2005, 10:05:16 PM »
Is there any debris floating in the coolant? Something that looks a little like pepper maybe? I could be you have a head gasket leak and the cylinder pressure is pressurizing the cooling system. The bad thing about this is that you may not develop the head gasket leak until the engine warms up. One thing you can try is to pressure test the engine and check for air bubbles in the radiator. I know this is not what you wanted to hear, but its the only suggestion I have.

ludedude

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Coolant Problem - What's Next???
« Reply #2 on: November 28, 2005, 10:21:18 PM »
Yup, if you ran it with lack of coolant, I bet your head gasket is gone and possibly your head is warped....well yours is..I mean the pilot head  :P

PilotSniper

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Coolant Problem - What's Next???
« Reply #3 on: November 28, 2005, 10:47:14 PM »
Thanks guys! I think we might have a winner here!!! The fact that the radiator hose was originally kinked caused the engine to overheat, which tapped-out my mechanical seal. All that is fixed, but the remnant of the original overheating must be exactly what you are describing. I took a quick look into the radiator just now and I've got the dreaded floating pepper indicator. I guess my next step is to order a head gasket and tear that puppy open. Well, it's not the news I was looking for, but at least it gives me a direction in which to go along with some badly needed hope for an end to this problem. I was really, really stumped on this one!

Since I've probably warped the K-Fab head that's currently installed (or at least the dome) and can't get a replacement for it, what head is the popular recommended replacement, along the lines of the K-Fab head (i.e. two-piece design, centered dome, etc.)??? If such an animal exists, where can this head be purchased???

Thanks again guys!!! I appreciate the help!!!
I started out with nothing and I still have most of it left!  :shock:

PilotHawK

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Coolant Problem - What's Next???
« Reply #4 on: November 28, 2005, 11:21:27 PM »
You can lap the head flat again. Using a piece of 220 or finer grit wet/dry sandpaper taped to a 1/4" or thicker piece of plate glass placed on a solid surgace (a lap stone would do better, but I doubt you have one at home) Tape the sandpaper to the glass and spray it liberally with WD-40. Using slow circular or figure 8 motions you can flatten the head. If you use machinists blue dye, you can see the high spots clearly as they are sanded off. Of course if you don't want to do any of this you can take the head to a machine shop and have them resurface the head for you. I bet you could even get Moskito to resurface the dome for you.

If the dome is "warped" most likely the top of the jug is out too. You may be best served by pulling the jug and having it machined as well (or lap it as previously mentioned).

PilotSniper

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Coolant Problem - What's Next???
« Reply #5 on: November 29, 2005, 12:16:41 AM »
Hawk,

I don't think I'll be lapping anything in my lifetime, but thanks for the lesson!

I'd rather send my stuff out and have it machined. Also, I don't want to put Skeeter out of his way, so if there's another replacement head that has the qualities of the one he created, I'll look into getting one (if I find that I need it).

As for the cylinder, is there an alternative to spending $300 for a new one, then sending it over to ATV Racing and spending another $410 to have it ported and polished??? I currently have the ATV Racing modded jug, like it, and would like to continue to use it (unless I can't, due to the possibility of excessive warping). I'd like to see what my options are. Any advice?

I've used Bill Moeller's services at Bore-Tech in the past with great success. I know I can get some machining done there, as well as having him fit the correct Wiseco piston to my jug, but does anyone know if he can lap the head and jug, if needed?

I apologize for all of the questions, but I know you guys have probably "been there and done that".

Thanks again!
I started out with nothing and I still have most of it left!  :shock:

PilotHawK

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Coolant Problem - What's Next???
« Reply #6 on: November 29, 2005, 12:46:20 AM »
If you send me the jug and head I'll take care of it for you.

PilotSniper

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Coolant Problem - What's Next???
« Reply #7 on: November 29, 2005, 07:51:49 AM »
Quote from: "PilotHawK"
If you send me the jug and head I'll take care of it for you.


Thanks Hawk! That's cool for you to offer!!!

Let me get some time so that I can dig into the top end and see what surprise awaits. We'll see the damage and take it from there. I hope it's not bad... :cry:

Thanks again for the offer!
I started out with nothing and I still have most of it left!  :shock:

ludedude

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Coolant Problem - What's Next???
« Reply #8 on: November 29, 2005, 10:34:30 AM »
Lapping's not that big of a deal Vic, you did a complete rebuild...I'm confident you can perform the needed lapping ;) I be surprised if you cannot use the head and cylinder again, fear not, I'm sure they're useable again after some massaging ;)

PilotSniper

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Coolant Problem - What's Next???
« Reply #9 on: November 29, 2005, 02:46:36 PM »
Quote from: "ludedude"
Lapping's not that big of a deal Vic, you did a complete rebuild...I'm confident you can perform the needed lapping ;) I be surprised if you cannot use the head and cylinder again, fear not, I'm sure they're useable again after some massaging ;)


Thanks for the vote of confidence bro! It's always my fear of going into uncharted territories that makes me shy away from all of the "complicated" stuff. I guess you're right, though. Had I not jumped into the complete rebuild, I wouldn't have learned how to do any of the things I now know how to do. I'm trying to position my days this week to see if I can get some time to do a teardown of the top end and see what I'm really dealing with. After PilotHawk and you enlightened me, I'm 100% certain that this is what's going on. I guess we'll find out soon enough how bad the damage actually is.

No worries! I'll keep you posted and, hopefully, I'll be taking a pic of a bad gasket and not a badly warped head and/or jug!!!
I started out with nothing and I still have most of it left!  :shock:

ludedude

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Coolant Problem - What's Next???
« Reply #10 on: November 29, 2005, 03:47:16 PM »
take pictures as soon as you remove the head...don't wipe the gasket or the head/jug...you can look for signs of the coolant leakage on them ;)

PilotSniper

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Coolant Problem - What's Next???
« Reply #11 on: November 29, 2005, 04:26:10 PM »
Will do! Trust me, I want to get rid of this problem in a BAD way!!! :(
I started out with nothing and I still have most of it left!  :shock:

Tman

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Coolant Problem - What's Next???
« Reply #12 on: November 29, 2005, 04:59:15 PM »
Notice Lude's familiarity of what to do exactly?  :roll:

PilotSniper

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Coolant Problem - What's Next???
« Reply #13 on: November 29, 2005, 05:09:41 PM »
Quote from: "Tman"
Notice Lude's familiarity of what to do exactly?  :roll:


Haha!!! Are you implying that "he's been there and done that" already??? :wink:

If so, THAT'S EXACTLY WHAT I NEEDED BECAUSE I COULDN'T TAKE ANOTHER DAY OF THIS UNCERTAINTY!!! Call me crazy, but I never thought I'd be happy about having to tear into my engine!!! Wooohooooo!!!  :mrgreen:
I started out with nothing and I still have most of it left!  :shock:

PilotSniper

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Coolant Problem - What's Next???
« Reply #14 on: November 29, 2005, 09:27:28 PM »
Here are the pics I promised. I decided to tear into it tonight after work. What's the sense of waiting to find out the bad news? :lol:

Can anyone see anything abnormal? I tried to find some sort of negative indicator, but my untrained eyes don't seem to find anything. The only thing that struck me as strange was that the dual-layered OEM metal head gasket was warped when I removed it. From memory (although I'm not 100% positive), when I've removed this gasket previously, they have always laid flat. Is there a remote possibility that I might just have a bad gasket??? Also, what are the chances of having a small heat-related crack somewhere down in the coolant-flow area of the jug? I remember seeing something like this online once. This jug has been worked by ATV Racing, so there's less meat in there and more chance of a debilitating stress crack to occur. What do you think???

Please click on each picture to see a larger, more detailed picture.
I started out with nothing and I still have most of it left!  :shock: