Another 470 Leaking Coolant

[SDSeville]

Well, I was getting ready for a big trip to lake Mohave next week and just noticed slow drips of coolant leaking from the weep hole. I have noticed a very slow loss of coolant lately (about a cup per 3 to 5 hours of running) and this is obviously where it is coming from.

I know the seals must be bad and I have read about the very involved repair. My question is -- how fast does the leak progress and would it need to be done before my trip next week? Does delaying the repair make it worse? My engine always runs at about 140 F and has never gotten hot, including my last 4 hour trip last weekend.

1986 Sea Ray 19' BR

 

[stonyloam]

Re: Another 470 Leaking Coolant

I would think a few hours on a trip would be OK. The main thing is to keep the weep hole open so the coolant leaking past the first seal drains out before it puts pressure on the second seal and leaks into the crankcase. Keep an eye on the coolant level, oil, and temperature, carry a little extra coolant to top off with. The replacement is not too bad if you have room to pull the rotor off of the crankshaft. Should be able to do it in one day. Lots of help here.

 

[boltonranger]

Re: Another 470 Leaking Coolant

Well; If it were me.... I would keep coolant with me in the boat and check it during midday of my trip.
That is assuming you have a cool down period. The seals are designed to fail on the safe side.
The outer one gets your attention before the inner one fails and coolant gets to the oil.
Is your oil clear? Milky means water has gotten in there. They don't fail all at once; but your mileage may vary. Others may have better advice; but If you check the coolant level and the dipstick periodically I don't see a reason to cancel the trip.
-br

you beat me again Terry!

 

[Eric 3.7LX Alpha 1]

Re: Another 470 Leaking Coolant

I agree with the others. With the rate your leaking, you should be fine for another trip.

Keep a close eye on your temp gauge, and bring some extra water or coolant.

 

[SDSeville]

Re: Another 470 Leaking Coolant

The oil is clear. I will make sure the weep hole is completely clear and give it a shot. Are there any coolant additives I can use to temporarily help keep the leak slow? Fiberlock, Leak Stop, K-Seal...? I will be doing the repair when I return from Mohave.

 

[SDSeville]

Re: Another 470 Leaking Coolant

Ignore the stop leak question. Searched a little more and found that is a BAD idea.

 

[SDSeville]

Re: Another 470 Leaking Coolant

Are there any videos of this repair out there? I checked youtube and could not find any.

 

[SDSeville]

Re: Another 470 Leaking Coolant

It has been over a month and I have only lost about a quart of coolant (a few ounces at a time and immediately replaced), engine temp has been great, and both oil and coolant look clean. However, after I ran it on muffs the other day, it started to slowly leak through the weep hole even when the engine is not running. So, I am finally going to replace the seals.

Are there any videos or detailed threads of this repair out there? I have searched but could not find anything?

 

[stonyloam]

Re: Another 470 Leaking Coolant

Here you go: Mercruiser 470 coolant leak Don't worry, you do not need a lot of special tools, and if you have room to remove the rotor you do not have to touch the front motor mount. A harmonic ballancer puller borrowed from Autozone will get it off. May have to imprivise a tool to get it back on. Lots of folks here to help.

 

[SDSeville]

Re: Another 470 Leaking Coolant

Thanks Terry! My local Autozone said they have both the harmonic balancer puller and the installer. I plan to order the parts this week and get started early next week.

 

[Eric 3.7LX Alpha 1]

Re: Another 470 Leaking Coolant

Here is another nice article replacing the seals and speedi job, with some good pictures. It gets side tracked a little bit but thumb thru it, worth it...

Discussion Forum: Weeping about the Weep Hole

You can get the new seals from any Mercruiser dealer or online Quicksilver# 26-97530, there are (2)

 

[SDSeville]

Re: Another 470 Leaking Coolant

Thanks Eric. Great thread.

 

[SDSeville]

Re: Another 470 Leaking Coolant

Well, how is this for procrastination. I planned on doing this project last August and just started yesterday. ...and I can't blame the weather.

I used the Stern Drive instructions, but skipped a few steps, such as lifting the front of the motor and heating up the impeller bolt. Mercruiser 470 coolant leak

Here she is before I started


Here is the harmonic balancer removal tool borrowed from Autozone. They sell them for only $20 if you will have another occasion to use it.


Balancer off. The stator is a mess. Power steering fluid (blew a hose last summer) and coolant all over it. What can I clean it with? I was thinking brake cleaner.


Stator off

 

[SDSeville]

Re: Another 470 Leaking Coolant

Here is a crappy picture of the impeller.


Impeller is off. Does this look right? Shouldn't I see more of a seal here? All I see is the lip/spring sticking through.



Somebody has obviously been in here before. There is gasket sealer everywhere.

 

[SDSeville]

Re: Another 470 Leaking Coolant

The next step is removing the timing cover. Any advice on the razor knife trick to keep from tearing the oil pan gasket? I don't think I have seen a thread where that has actually worked.

Also, the instructions say there are "approximately 5 screws" going through the oil pan into the timing cover. I can only locate 3 bolts under there.

 

[Bt Doctur]

Re: Another 470 Leaking Coolant

I suspect at least 2 pan bolts are there too. Best to loosen the pan bolts and drop the pan an inch or two.

 

[stonyloam]

Re: Another 470 Leaking Coolant

The next step is removing the timing cover. Any advice on the razor knife trick to keep from tearing the oil pan gasket? I don't think I have seen a thread where that has actually worked.

Also, the instructions say there are "approximately 5 screws" going through the oil pan into the timing cover. I can only locate 3 bolts under there.

As I recall mine came out OK. If you have trouble with the gasket just make a new section out of a sheet of gasket material. I would not loosen the pan, just use a razor to cut the old gasket flush with the sides. Use the bottom of the cover for a templet. A little extra sealant in the corners should seal it up. Yeah I think there are 3 bolts. Take care and use a torque wrench when you reinstall the cover, it is pretty easy to crack if you overtighten. Good luck.

 

[SDSeville]

Re: Another 470 Leaking Coolant

Thanks Guys. I plan to take the cover off in the next couple of days. I will let you know how it goes.

As you can see from the pics above, my stator is filthy. Is it safe to clean it with brake cleaner?

 

[stonyloam]

Re: Another 470 Leaking Coolant

As you can see from the pics above, my stator is filthy. Is it safe to clean it with brake cleaner?

I would be a little wary of the brake cleaner, pretty strong solvent, might soften the varnish insulation on the stator windings. A milder degreaser might be safer. Check the label to see if it is OK for electrical parts.

 

[ericcarr2000]

Re: Another 470 Leaking Coolant

Seville, when I had to replace my seals with the speedisleeves, all I really did to make sure I didn't tear the oil pan gasket at the bottom of the timing chain cover was to get a NEW exacto knife and make a cut along the pan rail. All I did was put the knife between the oil pan and the block rail and made a smooth cut. Once I was done I put a small amount of gasket sealer on there and installed it and torqued them down to specs. Not all that bad of a job really. Had mine done in a couple of hours.
I tell you what, having that ole 3.7 merc really made me get my tools out and learn bunches about that particular motor. Since then Ive moved up to a big block with a Bravo drive on her....
Best of luck. Oh yeah, it you need any, I have a new set of lifters it you'd like them.