2006 M35x oil & antifreeze loss

[robbins67]

Have a 2006 M35x with 195k and am losing oil and coolant. I have no visible leaks and car does not smoke but I go through approx 2 qts of oil every 7k miles. Also I have had to fill the antifreeze resivoir once in the last 18 months. Again I have no leaks for the antifreeze. I do know that I have oil leaking in the rear driver side spark plug port in the plug closest to the windsheild. I know to fix that I need to replace the entire valve cover.

I am wondering where the antifreeze would be going or burning? Also that seems like a large amount of oil loss if only going through that spark plug area. I dont see where it would be leaking. Any thoughts on repair?

[flex128]

I had the same problem whit my antifreeze if you have your stock intake system check under the part thats over the radiator the radiator has some seal that tends to go bad after a wile it burns the antifreeze when it gets hot because a small amount leaks from the top so it never falls to the floor to show you its leaking

[svard75]

The entire reservoir was completely empty within 18 months? Was your system full of air or something? Did you do your own coolant flush before this time? Coolant has a high boiling point but if your thermostat was broken then I can see the coolant slowly evaporating. It could also be the rad cap spring opens up much sooner than it should allowing the coolant to leak down to your under engine shield. Maybe it's just enough that it never leaks down for you to visibly see. If you suspect the engine is burning coolant smell your exhaust. If it smells like burning sugar you'll need to rebuild the engine.

[CPJ LB]

oil and antifreeze loss --- could be initial symptoms of blown head gaskets....

get it checked ASAP....

[SStroud90]

Hey Robbins67, my M35x just hit around 100k miles at the beginning of this Fall season. I was noticing a significant loss of oil myself, come to find out my oil was leaking down the side of my engine as well as into the spark plug tubes. The issue is that the rubber seals and gaskets within the valve covers go bad after awhile, and unfortunately the only fix is to replace the entire covers themselves. I did the job myself and posted a writeup near the bottom of this thread

post6511446.html

Three months later, not a drop of oil lost. My current issue, however, is my radiator as the seal between the top tank and the metal body has gone bad and it is leaking. I would've just like to replace the seals and salvage my radiator, but it has deteriorated rather quickly and with a good hard bump in the road, has burped coolant all over my belts, fan, and floor. My car is sitting in my garage again and I am currently purchasing another radiator by Denso and will soon flush my system and replace the bad radiator.

If you haven't yet, I suggest you have your radiator searched for coolant leaks/cracks as well as have your engine valve covers checked for leaking oil.

[robbins67]

Thanks for the tips. I did find a oil leak that was caused by a bad oil cooler seal. I replaced that seal, so one leak down. I will work on replacing a valve cover next to fix the oil in spark plug tube. Will check on the radiator leak as well.

MSVARA, I am sure that I did have air in the system, the reason that I checked the coolant level was due to the fact that I could hear the sloshing of liquid when driving the car. I filled the coolant reservoir and called it a day since the sound went away. I checked again (18 months, 30k miles later) and it was empty. It doesn't overheat, no sloshing noise and runs well.

I really like the car and want to keep it going as long as I can. Thanks for the help

[svard75]

Is it the overfill reservoir which is empty after 18 months? Does your exhaust smell sweet? let the car warm up then have someone rev a few times. Sniff the exhaust. If it's sweet or like burnt syrup then you're burning coolant and will likely need to rebuilt your motor.

[SStroud90]

Quick question on the coolant system guys. I am replacing the radiator with a Koyorad and was wondering if there is anything wrong with the traditional way of flushing the system with the water from a hose? Also, are those store bought 'flush fluids' necessary in any way? Thoughts or experience tips are appreciated.