Oil In Coolant, Critical Condition?

[Cheechako]

Originally Posted by Tim R.

A quick and dirty test would be to run your engine and while it is still cool, remove the coolant pressure cap. A blown head gasket would likely cause some bubbling/foaming of the coolant and even cause it to overflow.

Yeah, keep in mind If an oil passage through the headgasket is leaking into an adjacent fresh water passage, you wont see any bubbles in the coolant while running... not sure if the 2Gm has oil passages through the head gasket or not though....
It should be fixed properly before you do ruin your engine. You could try retorqing though....

[sww914]

Simple question, simple answer from a mechanic. Now.

[Neo]

We are in the process of replacing the head gasket on our 2GM20F. The encouragement from this forum helped us to do the smart thing.

I removed the alternator, heat exchanger and water pump yesterday. No real problems, except I had to use a very narrow set of electrical pliers to hold the base of the electrical connections on the alternator while unscrewing the terminal nut with needle nose pliers. A little messy. Also had to whack the heat exchanger with a 2x4 to unfreeze it after the bolts were removed.

I will remove the valves and injectors after work today. The engine looks so cute now that it's naked. The water pump was bigger than the head.



Questions:

1. Is it common practice to replace the head bolts and/or nuts? My brother in-law told me that they stretch over time, so should be replaced.

2. Can someone recommend a machine shop in the Boston area to have my head checked?

Many thanks,
Neal

[hellosailor]

Neal-
Some bolts, on some engines, only get used once. Others are re-useable. The factory service manual for your engine would be the answer to that if no one is dead certain. Typically, it is the studs for the cylinder head that are replaced, but this also applies to connecting rod bolts. A factory manual *may* be available if you ask the reference librarian at a major library. Often they have online subscription access and a way to make printouts, if the manual is too pricey or too slow to ship.

If you are new to engines, buy a bottle of NeverSeize and a couple of Loctite (red and blue). The NeverSeize puts the 2x4 out of work, and the Loctite is for anything else.

[Neo]

Originally Posted by hellosailor

Neal-
Some bolts, on some engines, only get used once. Others are re-useable. The factory service manual for your engine would be the answer to that if no one is dead certain. Typically, it is the studs for the cylinder head that are replaced, but this also applies to connecting rod bolts. A factory manual *may* be available if you ask the reference librarian at a major library. Often they have online subscription access and a way to make printouts, if the manual is too pricey or too slow to ship.

If you are new to engines, buy a bottle of NeverSeize and a couple of Loctite (red and blue). The NeverSeize puts the 2x4 out of work, and the Loctite is for anything else.

I have the shop manual, and it only suggested replacing head studs and rocker arm studs if they have damaged threads.

I also have the red and blue. Thanks.

[River Cruiser]

Re-using the head bolts should be fine, make sure to use a high quality torque wrench & follow the tightening sequence. Most call for re-torquing head bolts after a few hours run time.

[Cheechako]

Clean the threads up well before re-using the head bolts and torqing them. Yeah, if the head's off, good time to have it checked for cracks and the valves and guides ground. I wouldnt remove the valves, let the shop do that.

[Neo]

Wow! There was more oil in the cooler than I expected!



We’re in the process of cleaning up the heat exchanger while the head is in the shop, but can’t remove it from the cooler. The sleeve and the exchanger should slide right out of the cooler. No chance. I don’t want to bang it out, so I descaled with vinegar, rinsed and treated with WD40. No good. I even gave it a bubble bath. The seawater passages in the exchanger were completely clear and look to be in very good shape, and the cooler has a lot of rust in the freshwater passages but otherwise seems solid. I should probably replace the gaskets/o-rings and be done with it. Suggestions?



Is there a treatment I could use to clean up/ prevent rust in the freshwater passages/compartment?

[River Cruiser]

Any resolution to your problem yet, & any obvious culprit?

[Neo]

Epilogue

2012 Season:

1. The engine required either no throttle or high throttle to start, depending on who was doing the starting. Often times it would require 30 seconds of turning over before it would hesitantly start after multiple attempts.

2. Visible smoke coming from exhaust, even after warming up

3. Burned approximately 1 cup of oil per 8 hours running time

4. Fuel smell. Fuel leak on low pressure side dripping into catch pan under engine. Cleaned out almost two liters of oil/fuel at end of year.

5. Discovered lots of oil in coolant. Had built up over at least two years based on oil stain in coolant overflow canister.

Off Season:

1. I removed and cleaned the mixing elbow, was completely blocked

2. I replaced the head gasket. They identified an area on the gasket that might have been the problem. Lots of carbon build up in cylinders, I could not see much for cross hatching. I had the head pressure tested and resurfaced, new rods.

3. Installed new injectors

4. Installed new lifter pump (low pressure fuel pump)

5. Flushed cooler, replace all cooler seals and gaskets

6. Adjusted valves

7. Replaced all the freshwater coolant hoses

8. Painted valve cover and cooler

2013 Season after 40 hours of run time:

1. Engine starts first try every time at about 1/2 throttle

2. Smoke not really visible after engine warms up

3. No fuel smell, no fuel leak

4. No oil in coolant

5. Have confidence this year to run her harder. She doesn't seem to like 2800 rpm, which is recommended, (a little too much vibration for me), so we run her at 2600rpm. And we blow her out at 3100 rpm every few weeks, lots soot comes out.

6. She still burns about 1 cup per eight hours run time, but I think it is almost one cup for every time the engine is run. Maybe the rings tighten up after the engine warms up.

So, there was oil leaking past the head gasket into the coolant, but there was no coolant getting into the oil.

Blocked mixing elbow probably had caused difficulty starting engine.

Now that I can't smell diesel, I can smell the head.

Maybe do a ring job next year????

[MARINE ENGINNER]

dear neo
good to hear that your yanmar is going slowly to a perfection
about the ring job consider measuring your cylinder liners as per manual.if you have not exceeded the wear limit make a honing of the liners plus new rings to stop the consumption of the oil.

[Dockhead]

Remember oil consumption could also be valve guides.

If it were my boat, I wouldn't leave it like that. Leakage between oil and coolant circuits can be disastrous, and such leaks don't just heal themselves (they might go into temporary remission). You've got enough mechanical issues to be worth overhauling the engine, before something more serious breaks. I would have it out and and take it apart, evaluate crankshaft journals, rods, camshaft bearings, camshaft lobes, tappets, rocker arms, flatness of block and head, and all the other usual things. Hone the bores or replace the liners as necessary. Have the heat exchanger boiled out or replaced. Have the head done with new valve guides, regrind or replace the valves, mill flat if needed. Then put it all back together with fresh bearings, gaskets, rings, etc. Now won't that feel better? It's much easier and more pleasant to do it now while it still runs, rather than after it's thrown a rod through the side of the crankcase (and does your boat go on the rocks when that happens?). A lot cheaper, too.

[Dockhead]

Originally Posted by Neo

Wow! There was more oil in the cooler than I expected!



We’re in the process of cleaning up the heat exchanger while the head is in the shop, but can’t remove it from the cooler. The sleeve and the exchanger should slide right out of the cooler. No chance. I don’t want to bang it out, so I descaled with vinegar, rinsed and treated with WD40. No good. I even gave it a bubble bath. The seawater passages in the exchanger were completely clear and look to be in very good shape, and the cooler has a lot of rust in the freshwater passages but otherwise seems solid. I should probably replace the gaskets/o-rings and be done with it. Suggestions?



Is there a treatment I could use to clean up/ prevent rust in the freshwater passages/compartment?

Rust in the freshwater side is bad. It indicates not changing the coolant often enough, or not using coolant with the right anti-corrosion package. You should use 50/50 pink automotive coolant and deionized water, and you should change the coolant every two years. The pink coolant has anticorrosion additives in it which prevent this rusting, but they are gradually used up over time.

Rust in the coolant can grind up your water pump bearings and seals. It's abrasive. It can also clog up small passages. It's worth taking care to prevent it.

[Cheechako]

5. Have confidence this year to run her harder. She doesn't seem to like 2800 rpm, which is recommended, (a little too much vibration for me), so we run her at 2600rpm. And we blow her out at 3100 rpm every few weeks, lots soot comes out.

That engine should be perfectly smooth at 2800+ rpm. I dislike running that high also, but not due to vibration. If you have vibration up there something is amiss. If it is hard starting and consuming some oil.... see the thread by SailorChic... regarding broken piston lands... "had nothing to do so removed the head..."

[sailorchic34]

While the engine is running, take the oil fill cap off and see if you get any grey/oily smoke out the hole. Though if the engine starts easy, rings are not too bad. Though could be a bad oil control ring and still have good compression.

Does seem like a good bit of carbon in the cylinders, by the ridge of carbon at the top of the aft cylinder.

How many hours on the engine?