Coolant, if you can even call it that anymore, in my '92 is shot.... I'm planning on installing a flushing tee in the upper heater hose (to facilitate refilling, just pull the cap instead of having to pull the hose). I would like to flush the system out instead of just draining and refill. Since the engine is aluminum, are there any recommended products to use to flush the system? Or would I just be better off with plain water?

thanks
howlinowl

 

Many, many out there, and I use NONE.

Read the labels VERY carefully, as use with alloy on some is restricted.

I use fresh water as a flush, and demin water on refill.

If the car has been running warmer than it should, I remove the radiator and have it professionally flushed.

The header tank on the LH inner wing (guard) is usually FULL of mud, as is the atmospheric tank inside the LH wheel arch (pain to get to).

 

I'm a Mercedes Benz guy, the recommend citric acid flush on their alloy engines and it did seem to do a good job of cleaning the engine in my cars.

It's not as aggressive as the chemical deals in the shop. You can either buy it from an MB dealer for $20/lbs or from a novelty food store (asian super market) for about $4/lbs.

The way I do it on the MB is as follows:

1) Remove the thermostat and replace the housing.
2) Drain the radiator and refill with water a couple of times in between short runs.
3) Drain again and then use a de-oiling agent (dish washer powder mixed with water on the next refill) and run for 15 minutes
4) Drain radiator and refill with water, then run for 15 minutes intervals 4 times.
5) Mix in 1lbs of citric acid with water and refill.
6) Run for 15 minutes and then let it sit for a while (until engine is cool)
7) Drain radiator and refill with distilled water, then run for 15 minutes intervals 4 times.
8) Drain radiator and add high quality long life coolant like zerex G05.

 

On the Jaguar V12 if you remove the thermostats you will certainly overheat the car. The radiator will see no flow. On this engine I would leave the thermostats in place and at the end of the process install new thermostats.

 

Will it over heat in 15 minutes? If so, then it will be best to run the engine with the thermostats in place, but for longer intervals so that you allow the thermostats to open and the water to circulate.

 

15 minutes maybe not but you won't get any flush in the radiator