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cooling system ultra clean-out


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1998 Toyota Camry - 2.2L 4 cyl, A/T, 113K original miles -(2nd transmission) - no scans/codes.

This engine (5S-FE) is known for blown head gaskets.  Car was purchased approx 3 years ago w/78k.

No formal testing done to confirm head gasket leak. But...

Car was used for towing a pop-up camper (hitch still on car today). On taking possession, I did the following (engine) work: timing belt (factory original!) and water pump/pulley, new rad, both U/L rad hoses, t-stat, added Hayden trans cooler-bypassed factory one.

Other stuff done to make car ready for 1700+mile trip w towing trailer (1 axle).  No O/D used on trip cross-country per owners manual. Full fresh fluids/filters all around. Side note: Trans fluid/filter and differential fluid all changed - both ATF and especially differential fluid dirty/cloudy - all changed.  No problem on trip at all.

Car has had some problem w/ cooling system for awhile - coolant mix disappears from overflow res regularly.  Rad seems full most times checked- sometimes takes less than 1/4 gal to fill to top of rad cap.  NO milkshake under oil cap, when oil is changed (every 3K), or on dipstick - no white smoke from tailpipe.

2 winters ago, heater on, lower windshield starts fogging w/ steam (and anti-freeze smell). Probably loosing heater core (20+ y/o car).  I added Bar's Liquid Aluminum Radiator and Heater Core Stop Leak per directions (8.5 Fl. oz.) and followed through. Heater core steam/smell disappear w/in 2 days.  If blown head gasket was there, it may have been partially cured.

I want to thoroughly as possible flush the cooling system out (I will be hooking heater core hoses together to bypass core which will be replaced w/ new HC hoses at that time) and after flushing, use Steel Seal head gasket sealer to try and restore head gasket as much as possible.  My intent is to make sure that the cooling system is as viable as it can be w/o spending $15-1800 pulling the head/milling/valve set, etc.

Car runs fine now, minor MPG drop since I bought it, but I'm trying to stay ahead of the maintenance game.

Is there also some way to tell if other parts of the cooling system are gunked-up with rad/heater core sealant?

Please advise best way to clean the entire cooling system (less heater core which will be by-passed).  Thank You!!


2 Answers

Those "sealers" are just temporary bandaids. They may buy you a little time but that's about all. Relying on that stuff to hold up on a 1700-mile trip while towing a trailer is a real gamble.

You can visually check the thermostat to see if it's gunked up. (Might as well just put in a new one.) The radiator will have cold spots if there are clogs.

You can use a flushing kit to reverse-flush the cooling system.


Why would you want to mess up your engine with a sealer when you know the leak is coming from a bad heater core?  Have you done a compression test?  Are any of the spark plugs wet with coolant?