2011 Yukon XL coolant loss
12-14-2018, 04:00 PM
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2011 Yukon XL coolant loss
Vehicle has 202k miles. 2011 GMC Yukon XL Denali. 6.2L
No milk shake/mayo under oil cap or on dipstick. Oil color good. Nothing noted during last oil change.
No white smoke. No overheating. Does not run rough.
Dye shows no external leak. No visible leak.
Engine block test shows no hydrocarbons in cooling system (liquid stays blue)
However, lately every 2-3 days coolant level is low (about 1/2 inch) below “cold fill” line, when checked cold. Top it off when cold, level stays fine for 2-3 days then low again.
Where else can the coolant be going? What should I check next?
No milk shake/mayo under oil cap or on dipstick. Oil color good. Nothing noted during last oil change.
No white smoke. No overheating. Does not run rough.
Dye shows no external leak. No visible leak.
Engine block test shows no hydrocarbons in cooling system (liquid stays blue)
However, lately every 2-3 days coolant level is low (about 1/2 inch) below “cold fill” line, when checked cold. Top it off when cold, level stays fine for 2-3 days then low again.
Where else can the coolant be going? What should I check next?
12-15-2018, 08:12 AM
#2
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Check your floor boards, heater core might be leaking a tad and it might run out onto the passenger side floor. Or leak out where the water comes out from the A/C.
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12-15-2018, 11:24 PM
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What Mike said ^^^^^^ and: sometimes it'* hard to tell if coolant is there, especially in cold and especially if there'* only a little. To get around this, use a blue shop paper towel or a single layer of brown paper bag and press it onto the carpet really hard. if it'* wet you'll see where the paper soaks it up.
Also, check if the water pump is seeping a little. With that many miles on it, the water pump shaft seal may be getting tired.
Also, check if the water pump is seeping a little. With that many miles on it, the water pump shaft seal may be getting tired.
12-16-2018, 02:18 PM
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No sign of moisture in cabin/carpet, etc., heater works fine—good heat. Took it on a 4 hr round trip drive. Ran fine—temp 210 the whole way. Coolant low again this morning. Nothing on cardboard placed under vehicle. Still don’t see anything (ie “mayo”) in oil/oil cap, block test still not showing any combustion gasses in cooling system, don’t see any oil in coolant, still nothing showing up under UV light. Did see a few tiny droplets of water (clear) in oil cap—did not smell or look like coolant.
12-16-2018, 07:21 PM
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12-16-2018, 08:08 PM
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What would cause clear droplets? Wouldn’t it either be orange colored, like coolant, or the milky, mayo substance?
Trip was 1 hr each way, about 2 hrs city driving, and a few shopping stops.
Coolant was down about 1/2” from cold fill line—the same after the 4 hr trip as it was after 2 short 30 min round trips a few days ago. Other days of daily driving and coolant doesn’t drop at all. Not consistent.
In the last 3 weeks I have probably added about 1/3gal coolant total. Some days I have to add, then several days of not needing to add anything. Driving time is pretty consistent, but coolant loss is not.
Trip was 1 hr each way, about 2 hrs city driving, and a few shopping stops.
Coolant was down about 1/2” from cold fill line—the same after the 4 hr trip as it was after 2 short 30 min round trips a few days ago. Other days of daily driving and coolant doesn’t drop at all. Not consistent.
In the last 3 weeks I have probably added about 1/3gal coolant total. Some days I have to add, then several days of not needing to add anything. Driving time is pretty consistent, but coolant loss is not.
12-16-2018, 11:41 PM
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Condensation inside the crankcase. The oil cap is often the coolest place in the whole engine, and is the only place you can pop off so easily to inspect. Big question here is: how is moisture getting into the engine. Maybe does it normally do a lot of short non-warmed-up trips? . . . or maybe the engine bay gets pressure washed often? It'* interesting and possibly coincidental that an engine with a mystery coolant loss also has mystery moisture found.
When it gets mixed in with engine oil then pumped and thrashed about.
That'* a bunch. This makes me think the condensation in the cap is coincidental. Maybe.
This is the weird part.
I wonder if you use the rear heater differently from one trip to the next . . . ?
Also: Is the water pump leaking or even seeping a little? Check especially under the shaft seal.
That'* a bunch. This makes me think the condensation in the cap is coincidental. Maybe.
I wonder if you use the rear heater differently from one trip to the next . . . ?
Also: Is the water pump leaking or even seeping a little? Check especially under the shaft seal.
12-16-2018, 11:43 PM
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Put coolant dye in a few days ago and don’t see any traces anywhere. Would coolant dye show in oil, on the dipstick, or under oil fill cap? Or strictly on exterior?
Have tried just about every “driveway test” I know of or had suggested—coolant dye, engine block test, visual check of oil/filler cap/dipstick, coolant, hoses, floorboards, no white smoke, no drip spots under vehicle, etc. Doesn’t run hot or rough, heater puts out good heat.
All are negative except it loses coolant (but not everyday, even when driven) and some clear, fine water droplets under filler cap.
Have tried just about every “driveway test” I know of or had suggested—coolant dye, engine block test, visual check of oil/filler cap/dipstick, coolant, hoses, floorboards, no white smoke, no drip spots under vehicle, etc. Doesn’t run hot or rough, heater puts out good heat.
All are negative except it loses coolant (but not everyday, even when driven) and some clear, fine water droplets under filler cap.
12-16-2018, 11:50 PM
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Rear heater use is not consistent. Sometimes it is on, sometimes not. Even in front, sometimes dual zone sometimes not. Where would I check for loss related to rear heater?
I don’t see any visible leaking around water pump and no tracer dye residue either. Is there a specific place to check for seepage around shaft seal?
I don’t see any visible leaking around water pump and no tracer dye residue either. Is there a specific place to check for seepage around shaft seal?