Hi, Mr. Kilmer, I have a 2004 Civic Hybrid 1.3L 153k miles CVT that fluid sprayed around the area below the battery. There was a gargling slight screeching sound around the drive belt area (probably the water pump). Turned it off immediately. Checked the coolant in the radiator & it wasn't topped off as usual + found milky substance around inside the radiator tip & cap. Was scared that it could be a blown head gasket, so I checked if the engine oil cap & dipstick, thankfully it was normal. Rented a cooling pressure test kit & pressurized the radiator to 16psi to see if it would leak, but nothing, no pressure drop. The leak only showed up when the car is running & it was overflowing from the coolant reservoir & turned it off ASAP. When I opened it, it was like it was frothing milk not the normal blue fluid. I then tested the cap which wasn't holding pressure so I verified it was defective.
I get how it leaked, but I don't understand why it became milky. I've always read that it's from coolant & oil combining, but if the engine oil wasn't milky, it didn't overheat, & there's no white smoke from the exhaust, can it really just be a simple radiator cap replacement fix or do I need to worry about replacing the reservoir cap as well even though it was on tight? I don't see any cracks on the reservoir. It was only a couple of seconds after starting that it starts leaking (from cold engine) so how can it generate that much pressure to come out the reservoir cap frothing? Shouldn't it still be blue? Or was the milky substance just from starting it during the cool early morning temps?
I topped the radiator with a little Prestone 50/50 coolant since I couldn't see it from the top of the radiator. Should I also do a block leak fluid test? Do I need to drain & fill it with new coolant before that or should it be done as is? If the block test isn't necessary, do I need to completely replace the coolant or will it turn back to normal by itself? Thanks.
It was being driven daily for weeks so it wasn't condensation. Unfortunately, the radiator had an internal leak so the CVT transmission oil & coolant had mixed. The pressure didn't drop when there was coolant, but I heard a hissing sound from a relief hose on top of the transmission as I was pressurizing the radiator to force more coolant to drain. Checked the transmission oil dipstick, found milky residue on the tip + oil was nowhere on the level. Verified coolant was in transmission when it drained first then turned into chocolate milk 🙁 Removed heater core outlet hose & milky residue came out. It was never driven after we heard the noise & it leaked on the ground. What can I do to improve my 50/50 chance odds of salvaging the car?
Plan of attack:
Remove the thermostat & flush with a garden hose & back flush the heater core. As much as I don't want to use hard tap water, I don't really have a choice if I want to rinse it out of the cooling system.
Replace the radiator.
Use distilled water & coolant flush solution.
Use the used transmission oil to temporarily fill & rinse off the milk chocolate sludge.
Drive it about a week, then drain & fill the coolant & transmission oil, cross my fingers & see it that'll fix it.
Just recently replaced the hybrid battery so junking it isn't an option either 🙁 With the inflated prices of cars right now, it was a calculated risk. Worst case scenario is the transmission's shot as well, but one landmine at a time.
Your PCV valve is probably clogged and not working, 18 years old. Unfortunately, you need to remove the intake manifold to replace it. $$$. The milky substance can be the result of the engine not being fully warmed up to get rid of condensation. You definitely need to do the Italian Tune Up on a regular basis.
the radiator had an internal leak so the CVT transmission oil & coolant had mixed.... What can I do to improve my 50/50 chance odds of salvaging the car?
Unfortunately, this is a death sentence for a transmission.
Go get a transmission flush done at a shop and hope for the best.
