Advice Needed: Found Brown Sludge in Coolant Cap

[talibraza101]

Good day,

I have a 1971 FJ40 imported from Colombia, which I recently acquired last month. I just opened the coolant cap to find brown sludge pasted to the underside of the cap and opening (see attached photos). I plan on carrying out the following steps to remedy this:

1. Drain the old coolant
∙ Let it drain fully into pan
2. Flush with distilled water
∙ Close the drain, fill with distilled water, run the engine until warm, then drain again
∙ Repeat this 2-3 times until what drains out runs relatively clear
3. Final fill
∙ 50/50 mix of coolant and distilled water
∙ Fill slowly to purge air pockets
∙ Run with the cap off, watch for bubbles, top off as needed
4. Clean and reapply radiator cap.

Could someone tell me if my thought process is correct? Is this the correct way to remedy this problem? Any tips?

Thank you so much

PS. Dipstick looks good

 

[Mark Jennings]

There is a product you can purchase at your local AutoZone….Prestone Radiator Flush….i use it regularly. Also get yourself a flush and fill kit from Amozon. Read the label on the Radiator Flush, make sure it safe for aluminum (looks like an aluminum radiator on your rig). Pretty sure it is, since most new cars run aluminum heads/radiator.

So you add the flush to the existing coolant and get the engine hot, then drain. Then install the adapter Tee from the kit in the heater hose (the one from the cylinder head)…..hook up your garden hose (backflow adaptor in the kit), leave the radiator cap off and fill the engine/radiator. Make sure the heater control is Full Open. Then start and warm up the engine again, with the garden hose still hooked up. This Back Flushes the engine and radiator. Run copious amounts of water to get the rust and gunk out. Then if you want, go through your distilled water fill and flush.

You may need to do this several times. And once flushed, every couple of years.

Have fun….

 

[charliemeyer007]

Distilled water will help leach some of the deposits - I would use a good coolant system flush chemical with it. Triple rinse it out with regular water - then install your coolant mixed with the distilled water. I'm guessing they didn't run good coolant ever

 

[Mark Jennings]

Distilled water will help leach some of the deposits - I would use a good coolant system flush chemical with it. Triple rinse it out with regular water - then install your coolant mixed with the distilled water. I'm guessing they didn't run good coolant ever

Looks like they ran river water….

 

[77mustard40]

I've used ThermoCure in my 80 with success. I'd flush first with water then fill with distilled and ThermoCure and run it for a day. Flush again and refill with distilled and run it again for a day and repeat until you've got the system draining clear. Make sure to have the heater valve open to flush that as well (if it has one)

What you are seeing could also be due to mixing incompatible antifreezes or just plain neglect. Seeing something like that should have you questioning all of your fluids... think motor and gear oils. I'd change everything... and make sure to use GL-4 gear oil not GL-5 in the xfer case and transmission

EDIT: Make sure your block drain is not clogged from that crap as well.

 

[igotta40]

What came out of the block drain? Looks the same?

 

[talibraza101]

Thank you Mr. Jennings and Mr. Meyer, as well as other folks for their input. Appreciate all that you do.

 

[FJ404345]

Hate to say it but in Colombia they usually just put water in the cooling systeem, are you sure you found real coolant ?

Nice it has a fancy radiator cap !

 

[talibraza101]

Hate to say it but in Colombia they usually just put water in the cooling systeem, are you sure you found real coolant ?

Nice it has a fancy radiator cap !

You’re right! Most of the excretion was clear looking fluid. They really operate differently out there

 

[3_puppies]

Hate to say it but in Colombia they usually just put water in the cooling systeem, are you sure you found real coolant ?

Nice it has a fancy radiator cap !

You’re right! Most of the excretion was clear looking fluid. They really operate differently out there

several people have found out the hard way when they bring a rig into cold climates and the block freezes and cracks

 

[RevISK]

I concur with @77mustard40 on the ThermoCure. My 40’s block was full of sludge. I ran several flushes of just hose water, then a couple of thermocure flushes then several distilled water flushes and finally topped off with the red AF for Toyotas. What I got from the block drain was disgustingly disgusting. Make sure you run your heater (if you have it being from Colombia) as well.