Synthetic oil vs. a slow coolant leak...

[Shipo]

Hey gang, long time lurker / first time poster.

I just recently had a used oil analysis performed on our 1998 Dodge Grand Caravan with the 3.8 liter mill. This van had ~115,500 miles on it and ~7,500 miles on the Mobil 1 0W-40 in the engine at the time the sample was taken. I got the results from Blackstone on Friday and was alarmed to read that they've discovered that 0.29% of the sample was coolant and as such the Potassium (245) and Sodium (146) were way above the "Universal Averages". Fortunately all of the other sample numbers seemed to be quite acceptable and they confirmed this in their "Comments" section which read as follows:

"We found a high amount of potassium and sodium (key ingredients of anti-freeze) indicating that 0.29% of the sample was coolant. Luckily, it hasn't hurt engine wear at this point. A cooling system pressure check should find the source of the leak. 1.8% of the sample was fuel, which comes from idling/city driving. It didn't affect viscosity, which measured in the correct range for a 0w40. The TBN was 4.4, some active additive left. Air and oil filtration appeared normal. We suggest short (3K miles) oil changes until coolant problem is fixed. This is a Caution report!"

Thinking back on this issue, that van has used a quart or so of coolant per year since late 1998 when the engine got REAL hot while driving on some steep mountain roads. Assuming that event is what caused my slow coolant leak, we've now driven it for over 100,000 miles with some amount of coolant in the engine oil.

The good news is that I converted that van over to Mobil 1 (I'm thinking it was 5w30 at the time) around then and then over to Mobil 1 0W-40 in 2001 or so (I have other cars that specify the 0W-40 and it's just easier to have only one oil type in my garage).

So, with the above in mind, I now have a question. Is Mobil 1 good enough (assuming a 7,500 mile OCI) to continue to shrug off the debilitating effects of the coolant contamination (as it seems to have done for the last 100,000 miles), or should I step up to the plate and overhaul the top end of the engine (where I suspect the problem exists)?

Thoughts?

 

[LargeCarMan]

Shipo

I would install a couple of tubes of Aluma Seal or other brand name of coolant sealer. Keep the Mobil 1 in and continue with what you are doing.

If the oil is still doing its job and wear is normal, why waste some big dollars in repair bills with 100+K miles on the engine.

 

[Spector]

Well, for under $5 I would add a bottle of Barrs leak to the coolant and see if you can stop that leak, sounds like a minor head gasket leak caused by the overheating. this may or may not work but a very cheap fix at least for a while if it does work. It has for me on a couple of occassions. the coolant will damage the engine eventually, so, get that head gasket replaced or try the stop leak. to leave untouched is playing with fire!

 

[m2200b]

I'd use dino with lower oci at 3K or less and the above fixes to control the damage of coolant on bearings. Frequent changes will do more than syn ever could until you stop the leak.

 

[Vortec_4300]

Truthfully, are you certain that the nominal coolant leak was caused by the events you cited from almost 8 years ago?

It could very well just be a coincidence that you had experienced those problems; your leak may be the result of something which just occurred in the last few months or years.

Is it worth it (given the amount of reliance that you have on this particular vehicle) to gamble on an uncertain outcome, when it seems as if a reasonable solutions consists of a pressure test, 3K mile OCIs, and the potential for fixing the problem with the addition of a few GM coolant tabs? Even if you are looking at a few hundred $s worth of repairs, would you simply want to rely on the robust nature of a synthetic motor oil to compensate for a coolant problem with any number of unknown variables at this point?

I get the feeling that many folks want to believe that a top-of-the-line synthetic will alleve other problems that may occur in normal operation of their vehicles - in some cases, people really want to believe that an expensive synthetic will allow them to forego routine and required maintenance.

I'm not saying that this is your position, but just be wary of others who may advocate this kind of behavior. A good synthetic may keep you from experiencing a critical failure sooner than if you were using a cheap dino, but it won't put off the event altogether.

 

[fred0803]

Regarding the Barrs stop leak. I had a bad experience with the head gasket stop leak. Silver bottle, costs a little more than the standard stuff.
Thought I had a head gasket leak, did all the directions from Barr. Draining, filling with water, draining, let it sit etc. and then no heat was coming out. Clogged the heater core, and back flushing did work though. Drained that stuff out of there. It's like mud. Certainly has it's uses, but a bad experience for me.

My two cents is to use Havoline or another reasonable dino and change oil every 3000 miles, that way if coolant is in there, you are getting it out of there twice as quick. And the cost of Havoline turns out to be less than Mobil 1.

 

[Triple_Se7en]

Use the Bars Leak stuff & change oil brands because Mobil has a high sodium count in their oils.

Drop-down to a syn-blend & change at 5K with another UOA sample. Dropping down your OCI mileage helps minimize contamination. Your very small leak numbers should improve -- your sodium count should drop. Try either Castrol - Valvoline - Pennzoil next time.

just my backyard, amateur opinion here....

 

[Shipo]

quote:

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Originally posted by LargeCarMan:
Shipo

I would install a couple of tubes of Aluma Seal or other brand name of coolant sealer. Keep the Mobil 1 in and continue with what you are doing.

If the oil is still doing its job and wear is normal, why waste some big dollars in repair bills with 100+K miles on the engine.

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Thanks for the Welcome!

After seeing what Aluma Seal and other "Stop Leak" products do to radiators, I'd rather drive that engine into the dirt than to put those type of products in my radiator. Said another way, I agree with the rest of your post which essentially means, "Drive it till it drops."

 

[Shipo]

quote:

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Originally posted by Vortec_4300:
Truthfully, are you certain that the nominal coolant leak was caused by the events you cited from almost 8 years ago?

It could very well just be a coincidence that you had experienced those problems; your leak may be the result of something which just occurred in the last few months or years.

---

Am I certain? Absolutely not. That having been said, I've done all of the maintenance on that van since new and noted the consumption of coolant for the first time in 1999. Does that mean that the problem was caused by the high temp event in late 1998? Nope. Could it have come from the factory that way? I suppose. Could the problem have occured more recently? I don't think so as the problem has been fairly consistent for years.

 

[Gary Allan]

quote:

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Synthetic oil vs. a slow coolant leak

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(visions of "Alien vs. Predator" ..or perhaps "Running Man")

I'll put my money on the coolant leak in the long run. You do appear to be holding up well at this time.

 

[MN Driver]

I've never seen so three digit sodium and potassium without high wear, surprising to me. I've had two digit numbers for coolant contamination in one of my own cars over the same mileage that caused major alarm on this forum. Stop leak and a few short OCI's did fix it for me and wear went down but the car has since been sold to avoid other problems that were coming around the bend for that car.

 

[Clyde65]

You left out a lot of variables in your original post.

1) Can you turn wrenches?
2) What kind of shape is the rest of the van in?
3) Would the van be worth installing a new engine?

Recommendations:

A) Assuming that you turn wrenches, park the van under a cool shade tree, pull the intake and heads and replace the gaskets. Lay a straight edge across the bottom of the heads and check for flatness.

B) Run the van until the engine seizes and the pull the the whole engine for rebuild. (You turn the wrenches).

C) Run the van until the engine seizes and pull the whole engine for a rebuild. (You pay the labor cost).

D) Run the van until the engine seizes. Have it towed to the wrecking yard and have them pay you for the scrap metal.

Final comment: If you can turn wrenches, and you have the necessary tools and service manual; pulling the engine yourself can be easy yet time consuming. You have to ask yourself if the vehicle in question is worth your time? Only you will know the answer.

 

[Shipo]

quote:

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Originally posted by Clyde65:
You left out a lot of variables in your original post.

1) Can you turn wrenches?
2) What kind of shape is the rest of the van in?
3) Would the van be worth installing a new engine?

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A fair lot of questions

1) Yes, I can turn wrenches (and have a pretty fair assortment of them as well). Back in the 1970s I turned a wrench for a living and have done complete engine overhauls by the dozens. That having been said, I decided that engineering paid better and didn't get the sheets as greasy (even with lots of showers), so the last engine that I cracked open was the one on my 1970 Dodge Challenger (after a *former* friend blew the engine), and that was in 1982.

2) The rest of the van is in good enough shape that when I had tires put on it last fall the technician commented that he'd never seen a van of that vintage with that many miles on it in such good condition. Of course that still means that it ain't in show room condition, typical of even the best maintained family vehicles that have well over 100K on the clock.

3) Would it be worth installing a new engine? I doubt it; however, I simply cannot see the need for an entire new engine. Why? Well, even with nearly a buck twenty on the clock, it's still only uses a quart of oil in 7,500 miles. Not too shabby. To me at least, that means that the lower end is still in pretty darn good condition. Remember, I've used Mobil 1 in this thing since about the 15,000 mile mark, and as the oil analysis shows, there are no significant wear issues even with all of the coolant that has leaked into the oil.

As for your recommendations:

A) I'm really considering this as I'm thinking that a head gasket is most likely the culprit here. What gives me pause is that I really don't want to do all of that work only to find that one of the heads is either cracked or warped. With that in mind, simply by spending another $300 for a pair of reconditioned heads, I eliminate finding a problem with the engine apart and no parts to fix it with. Hmmm, assuming that I'm only leaking from one side of the V6, maybe I should only buy one new head.

B), C) and D)... I agree 100%.

 

[Ray H]

quote:

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Originally posted by Triple_Se7en:
Use the Bars Leak stuff & change oil brands because Mobil has a high sodium count in their oils.

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used oil analysis don't bear that out for Mobil 1. Shipo's got a serious coolant leak.

 

[m2200b]

Are you sure you're still at 1 gt coolant per year. I could chaulk that up to evaporative and other sources than the head gasket. But if you are using more than that now I'd guess you do have a head gasket leak that has gotten worse in the last 3-6 months.

Year 8 is a little early to toss the investment.
With those numbers I'd pressure test it and decide which head it is and recondition it or sell it before its a total loss.

 

[m2200b]

Nearly every GM runs ok with Bars Leak from the factory. I think your DCM can risk it.

 

[Shipo]

quote:

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Originally posted by m2200b:
Are you sure you're still at 1 gt coolant per year. I could chaulk that up to evaporative and other sources than the head gasket. But if you are using more than that now I'd guess you do have a head gasket leak that has gotten worse in the last 3-6 months.

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Yes I'm quite sure that the coolant loss hasn't accelerated recently (I check it at least at every oil change which is every three to four months). As for "chalking it up to evaporative loss", yes, that's what I've been doing for seven years now. Said another way, when I heard the news from Blackstone I was instantly surprised (because I hadn't suspected a problem before then) and suddenly not surprised as I intellectually tied it to my slow coolant loss.

quote:

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Originally posted by m2200b:
Year 8 is a little early to toss the investment.
With those numbers I'd pressure test it and decide which head it is and recondition it or sell it before its a total loss.

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Okay, I've been meaning to ask this. If I have it pressure tested, how does the tester divine which head is the culprit shy of partially disassembling the top end of the engine?

 

[Shipo]

quote:

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Originally posted by m2200b:
Nearly every GM runs ok with Bars Leak from the factory. I think your DCM can risk it.

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I've also heard that GM has had lots of problems with that new coolant of theirs, to such an extent that they've had to offer new engines to some folks and had other cars "Lemonized". No thanks, I'd rather treat the cause than the symptom.

 

[Ignatz]

Barr's leak in the (cheap) powdered tube has been keeping my 92 Escort alive for the last 50,000 miles. If I flush out all the antifreeze untill its clear water (about 3 flushes) my car will start running on 3 cylinders.(cracked head) Fresh antifreeze, distilled water and two tubes of Barr's leak and everythings fine. I've done an oil sampling last year and although Blackstone say's I have a coolant problem, theres no sign of engine wear. I'm doing 3,000 mile oil changes just so I can dump the poison out and look forward to the day when I look in the miror and see a cloud of white smoke....time to get a new ride!..Its been this way for about 4 years and its not getting any worse.

 

[therealdeal770]

quote:

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Originally posted by Shipo:

quote:

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Originally posted by m2200b:
Nearly every GM runs ok with Bars Leak from the factory. I think your DCM can risk it.

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I've also heard that GM has had lots of problems with that new coolant of theirs, to such an extent that they've had to offer new engines to some folks and had other cars "Lemonized". No thanks, I'd rather treat the cause than the symptom.

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Thats what scares me about my new Impala.At 22k it already has deposit in the coolant resovior