3.0L cyl. head

[joe1956]

Hi...dose A 1989 3.0L head have water passages in it.If so will the holes plug up easy?I had a over heating problem and I have checked everything else. But timing was way off 15 BTDC could that have done it. thank's

 

[Don S]

Re: 3.0L cyl. head

Lot's of things could be wrong, but with that minimal information there is no way of answering.
Go up to the Adults only sticky at the top of the forum and look at #1

 

[joe1956]

Re: 3.0L cyl. head

Sorry it's 1989 chev.3.0L omc outdrive.Been out 4 time no overheating problems.went out ran it about 10 min then steam came out of the overflow scared the H out of me thought it was on fire.The system is closed using antifreeze cooling the motor.Water from the impeller runs thought a heat exchanger then to the manifold then out.There was no water flowing from the impeller at idle but at 2000 rpm you get a lot but it it didn't cool down.Pulled off the thermostat cover it was full open (tested it when I got home working fine opens at 160)also pulled off exhaust riser started it ran it up to 2000 water was shooting out where it should.Engine was super hot had to call a friend to get me in.When I got home took off water pump is ok looks new.Flush the system manifold and riser not plugged.This boat has a heater coil in the cabin a lot of rust cam out of it not sure if water was flowing through. Going to bypass it not needed here.hope all this will help thank you

 

[Howard Sterndrive]

Re: 3.0L cyl. head

There was no water flowing from the impeller at idle

should be a healthy flow from the impeller at idle... like a garden hose with the tap 1/3 to 1/2 open

 

[chiefalen]

Re: 3.0L cyl. head

See this is the perfect example of someone buggering up a system by adding stuff that just don't belong, probably worked for 20 years then sold the boat knowing there were all kinds of problems.

1- install a new impeller, why i didn't post to check it is it already overheated and to go to the trouble of checking it you might as well install a new one.

2- If it were my boat i would yank the heat exchanger, that didn't come standard on a 3.0 omc 1989 motor. Go to a raw water cooled system.

3- Heater core in the cabin got to go.

4- You say you checked the riser and the manifold, did you check to see if the flapper broke off and is blocking the exhaust tube or fell down and is jammed into the lower part of the exhaust??

Pull the long hose that connects to the t-stat from the transom and see if pieces of a impeller is blocking the hose.

After you did all i posted above give it a run on the water after AFTER YOU DO A FULL TUNE UP and have it idling between 600-700 rpm in the water in gear.. 650 is good.

Post the results.

Good luck !

 

[Don S]

Re: 3.0L cyl. head

See this is the perfect example of someone buggering up a system by adding stuff that just don't belong,
3- Heater core in the cabin got to go.

That's a rediculous statement. Cabin heaters on boats are very common, even adding a water heater for domestic water systems on boats is not uncommon.

The impeller in the raw water pump is the first thing to check in any overheat of a marine engine since there a so many things that can cause even a new impeller to fail. After that you start worrying about all the other possibilities.

 

[chiefalen]

Re: 3.0L cyl. head

Yes a cabin heater is common, but not a option to buy from the factory. At least not that factory, and that year, and that setup.

Thus must have been a after market setup. So by the very definition, was shunted together.

So not " rediculous ". Was a bypass built into the system in case the core was blocked up as in a auto setup ??

Or was the water directed to the heater core directly from the motor and then routed to the t-stat?? Who knows ?

Remove the heater core from the system and leave it in place if you desire to run it down latter.

 

[Don S]

Re: 3.0L cyl. head

So not " rediculous ". Was a bypass built into the system in case the core was blocked up as in a auto setup ??

If the core gets plugged up you wouldn't get any heat, but it wouldn't effect the cooling of the engine.

Had the original posted said he just installed a cabin heater and now it overheats, well, then there might be something to it. But it's probably been working fine up till the impeller went south on him.

 

[chiefalen]

Re: 3.0L cyl. head

Maybe i wasn't clear of course impeller FIRST , run it , still overheats then down the list till we find the problem.

Never wanted it to go this far, i was agreeing and maybe was misunderstood.

 

[joe1956]

Re: 3.0L cyl. head

thanks chief ,don Heater core has been bypassed.I did find the flapper melted to the wall but it wasn't blocking much about 1/5 of the outlet at most.I have the impeller on order haven't pulled it out yet, and the gaskets for the manifold.Is A closed system that bad won't it will keep salt water out of the motor? ill do all you guys tell me.I may have got screwed on this deal but it's keeps me out of trouble and ill keep working on it till I fix everything.Can't work on it this weekend raining. Ill let you know how it's goes thank you for your time.

 

[chiefalen]

Re: 3.0L cyl. head

You know whats so great about banging your head on a wall, is how good it feels when you stop.

You get all of the flapper? So i was right on one thing flapper broke loose.

 

[Don S]

Re: 3.0L cyl. head

So i was right on one thing flapper broke loose.

Wow, pat yourself on the back, but a broken flapper isn't his problem. But hey, you know your stuff.
I will leave you to cure the problem for him.

 

[chiefalen]

Re: 3.0L cyl. head

Had a bad day Don ? Hope you have a better evening.

 

[joe1956]

Re: 3.0L cyl. head

Ok A update took impeller housing off wow what A melted mess looks like it was ran without water.(not me)Going to have to change it all.Is there a better way to get water into it than using muffs?It takes to long for the water to get up to the engine, all the new stuff may help.I had a old 67 with a omc on it someone but a car flush kit on it but doing that water is forced down to the impeller I don't think that was very good but it was always wet. thanks guys

 

[Don S]

Re: 3.0L cyl. head

If you have plenty of water going to the muffs, it will get water to the raw water pump very quickly. It will take 10 to 15 seconds to fill the engine and manifolds and start coming out the back of the boat after you start, but that is normal. The pump is in the drive and sees water almost immediatly so don't worry about that part.
You need the complete pump, housing and all if anything is melted. Those housings don't put up with burning impellers at all.

 

[joe1956]

Re: 3.0L cyl. head

update: Went to the lake yesterday engine temp was like this. Using a IR thermometer and dash gauge at 4000 rpm after 10 min. 170 to 175 and at idle 190 and is hot as it got and at 2000 rpm it cool back down to 170 or so.I did everything that chief said but left the closed cooling heat exchanger in. It has new impeller,tuneup 160 thermostat system full of 100% antifreeze lines not blocked,manifold have some rust in them but they flow well and the riser temp only goes to 120.Lake temp is 60 here worried that in summer it's going to get hotter.Is this ok or do I still have something wrong? Thank you Don and Chief both for your time it is appreciated by many I'm sure.