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My aging 2000 Lexus RX300

I have a 2000 Lexus RX300 with 230,000 miles on her. She has been a fantastic car, and has given my wife and I and lot of pleasurable miles. It has recently started to leak anti-freeze from around the cylinder heads (according to my mechanic). He said that this will probably lead to having to replace the head gasket, which apparently is a pretty expensive job ($2,500). I am wondering if there is anything that I can do to either fix or at least give the car some more life. I would like to get some more miles out of her if possible. I appreciate any feedback and ideas.

I’ve had success stopping head gasket leaks by adding soduim silicate to the coolant.

Look at auto repair catagory.

You can order a bottle of sodium silicate from a local pharmacy for about $25.00.


There are many head gasket “repair” kits at the local parts stores

There’s a variety of “miracle” products on the shelves at car parts stores that purport to seal leaking head gaskets. Temporarily at least. I’ve never tried any of them. “Bars Leak” is one mentioned on the Car Talk show I think.

Another idea. Retorq-ing the head bolts might help. The head bolts are supposed to hold the head tight against the block, squeezing the head gasket. You could ask your mechanic to try that. Sometimes to do so requires removing the cam shafts, so the economy of doing that would be suspect in that case. But if it simply removing the valve covers and giving the head bolts a tweak, that might be worth a shot.

That said, it’s highly unlikely any of the above will work longer-term, and the best course of action in my opinion – provided you want to return your engine to daily driver status – is just to replace the head gasket. The reason it is expensive is b/c the head is sort of like grand central station for the engine. Everything recirculation or coming in and going out of the engine, air, fuel, coolant, oil, it all goes through the head. So the head is pretty much connected to all the other parts, which makes it time consuming to remove. This job doesn’t need to be done by a dealer, so if your current mechanic is the dealer, price the job at some local shops too, preferably ones that specialize in Asian cars.

Edit: The $2500 price may include head and block resurfacing and a valve job. You may not need either of those services. Ask what the fee includes. Maybe you can get the fee reduced if inspection shows all you need is the new gasket.

You’ve gotten a long life from your RX. I’d move on, get a replacement as soon as you’re financially able.

Alumaseal works well on slow eternal leaks. You can get it at parts stores like NAPA or on

Bar’s leak is another cheap option, google it and the nuclear sub Nautilus. It did wonders. But I wouldn’t pay for new head gaskets.

If the rest of the vehicle is in good shape, where else are you going to find a reliable vehicle that you like for $2500?

First, I’d want to do a dye test to see where it’s actually leaking from. You add a UV sensitive dye to the coolant, run the engine per the directions in the kit, and view it with a blacklight. Preferable at dusk. Any leak path will light up for you. The kit is cheap and available at any parts store.

If it does appear to be leaking from the seam between the heads and the block (wherein is the head gasket), I’d want to do a compression test and a leakdown test. If the compression is good and there’s no evidence of a breech between the cooling jacket and the cylinders (if it passes a leakdown test) I’d vote to repair it. It is possible that the coolant is simply weeping between the water jacket and the outside world. That would not cause other damage, but it might be a sign that the head gasket is deteriorating. Changing it now could prevent expensive further damage.

My guess is that the first test will determine that it’s leaking from other than the headgasket and migrating along the crack at the head/block seam.

I would recommend strongly against making any decisions pending the results of these tests.

post back with the results.