87 Toyota MR2 Pennzoil 10W30 500 Miles

[redvalkyrie]

This is a rebuilt engine. Oil has been changed at miles 250, 500, 1000, and 1500 for break-in. Mostly short stop and go trips of 15 miles total or less with a once a week trip of about 40 miles highway. Rebuild was finished in August of this year, 2005.

Mostly gentle driving with no reving over 6000 rpm for this last change. Car did have a timing problem for about ten miles -backfiring, no timing advance-. Weather wise things have been up and down, with temps from below zero up to 60*F. Toyota oil filter.

Blackstone Report:

Since this is the 4th oil change since the rebuild, we are puzzled that there is still high
chrome (from rings) when all other wear metals look okay. It could be these rings are taking just a bit longer to wear-in. Our big concern is high potassium and sodium -both indicators of anti freeze contamination- in the oil. Are you losing coolant? The oil's viscosity was low measuring in the 20W range. Air and oil filtration were good. No fuel or water found. Suggest another short oil change interval and resample, to verify the elements of anti-freeze in the oil.

Aluminum: 3
Chromium: 7
Iron: 29
Copper: 2
Lead: 1
Tin: 0
Molybdenum: 202
Nickel: 0
Manganese: 1
Silver: 0
Titanium: 0
Potassium: 33
Boron: 50
Silicon: 15
Sodium: 34
Calcium: 1702
Magnesium: 7
Phosphorus: 628
Zinc: 692
Barium: 1

SUS Viscosity @ 210F: 56.4
Flashpoint: 400F
Fuel %: < 0.5
Antifreeze %: ?
Water %: 0
Insolubles: 0.3

Obviously, it looks like I have antifreeze leaking into the oil -I'm guessing through the head gasket-. However, I am pretty anal about this car and keep close tabs on everything and have noticed no coolant loss. My compression test came up even and good. My first test for exhaust fumes in the coolant via a block test kit came up okay -will be retesting again to confirm-. I will be doing a leak down soon. Plugs checked out okay and there is no sweet smell from the exhaust. The oil looks okay as well.

Does this coolant contamination appear to be significant enough that I should be getting some other signs? The engine runs perfect.

Could the potassium and sodium be coming from somewhere else? Perhaps the ceramic and teflon coatings on the pistons?

My current plan is to have the oil tested again in 500 miles and go from there.

Thanks
JP

 

[TR3-2001SE]

I don't thing the sodium and potassium are comming from any thing other that a small cooling leak. It has been my experience with rebuilt engines that they need some time to wear in before jumping to any conclusion. Give it time but continue to moniter by UOA. It is such a small leak that a simple stop leak fix may be in order.

 

[Al]

Its more than an even bet you have a coolant leak. I'd probably go change it in 500 miles and do another run before doing an analysis. At this rate of changing oil and testing, you will be able to buy a new engine.

 

[redvalkyrie]

quote:

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It is such a small leak that a simple stop leak fix may be in order.

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Interesting. How do you determine this to be a small coolant leak? I'm not up to speed with how to analyze the numbers other than comparing them to what they should be and going on that they seemed high.