Overheating with a strange twist

Hi, I have read numerous posts on here outlining most of the common problems to do with overheating.
One thing I havent been able to come across on here, is a problem like mine.

I have a 1995 Super Custom, with a 1kz-te engine (which, judging by a lot of posts, is a problematic engine on its own)

I have had it 6 weeks, and so far, I am far from impressed.
The big energy saving style light in the back goes when I bang it, the curtains stopped working between the time i viewed it, and the time i got home after buying it, it has a huge knock that shakes the whole van on start-up, and now the over heating problem.

I have opened the tap on the bottom of the radiator, and coolant comes out (no surprises there) but the water at the radiator cap is a very dark brown (almost like melted chocolate)

Having chocolate at the top, and green coolant out the bottom is obviously not normal.

At an idle, I can top the water level up to the brim of the radiator cap opening, then, when i apply some revs, instead of the level going down, it goes up, in turn spewing all my freshly added coolant over the left side of my engine.

Any ideas on how to solve the problem? or what I need to check/replace?

Hi,

On startup I have to let my glow plugs warm for about 5 to 10 seconds depending on ambient temperature or else cop a big kick on startup. This means turning the key to on position and waiting a bit before cranking it. Others have described theirs as needing no warmup time but my operator manual says to wait until you hear the preheat solenoid click before cranking. This can take up to 20 seconds. I don't need to wait that long but if I just crank it straight from cold I will get an almighty shudder that feels like the engine wants to tear out of it's mounts.

Looks like someone has mixed the red coolant (standard for this machine) with the green ethyl glycol which will give you the muddy brown colour. I know what you mean about the level normally going down on most cars when you rev the engine if you put the coolant in at the radiator. I would not expect any change in level to be seen at the coolant overflow tank as this should be separate from the pressurised system by the spring loaded radiator cap. The overflow tank does not hold pressure itself. On expansion some coolant escapes past the radiator cap via an overflow pipe into this tank. When the engine cools it sucks some back into the system. The proper level in this overflow/expansion tank is quite low when the engine is cold. It should not be filled full. I have to shine a torch in mine to see the level in relation to the indicator line. Hopefully someone else can help you more on this issue. Some vehicles have a switchable radiator blind which should be set to open for summer driving. It may be worth checking if yours has this.

Cheers,
Dave

Thanks for the tip on the glow plugs. I wait until the light goes out (which I was running with the assumption that the light went out when the glow plugs finished their job) I will wait a little longer, and let you know what happens.

The expansion tank takes the excess from the engine, which is already what I knew it should do, but the engine doesn't seem to take it back as it cools (which is a concern)

I hadn't thought about the possibility of mixed coolant types.

Where would I find the switch for the radiator blind if mine does in fact have one?

Hi,

I also need a torch to view the coolant level in the overflow tank  

If you have the 2 different types of coolants mixed, you will need to thoroughly flush the system with distilled/rain/demineralised water etc to remove the coolant from the system. If you do this via letting it drain under gravity, it will probably take about 6-7L, passed through about 6 times. Each time you have topped up with the clean water, you need to take the van for a spin around the block with all heaters going flat out to make sure that the thermostat has opened and old coolant is flushed from the heater circuits. Don't forget you may have 2 radiators, therefore 2 drain plugs.

Then add enough concentrate to make up the required strength and top up with distilled water. Also check the radiator drain plug to make sure it's not brittle and that it seals properly.

Before you do anything, it may pay to get a rise test done. This will check for a blown head gasket. I had one done as a precaution when I bought my van.

Also check to see if you have a blockage somewhere in the coolant system as having different coloured coolant at the bottom and cap end doesn't sound good. Not sure what colour you would get if oil & coolant mixed as the oil would certainly float near the top, hence the rise test.

I run the Tectalloy Gold coolant in my van. It's one of the green ethylene glycol based ones. Seems to work for my van.

Hope this helps.

regards,

Werner

The part that concerns me is the water coming out of the radiator with a few revs.I suggest you get the head gasket checked(a crack between the combustion chamber and the water jacket will lead to this problem)The large light could have a bad earth.I had the same problem with a connecting plug on the main power board in the light itself near the screw that holds the diffuser in place it was not connecting properly.

When you rev it the water pump will push the coolant out.

I'd try a complete drain down and refill.

The brown stuff may be a sealant additive?

Electric curtains may just need the runner cleaning, be very careful the contact strips are very fragile. Un hook the curtains from the ceramic sliders and see if they run on their own.

Where do I drain the system from?
It has 2 radiators, and i cant for the life of me figure out how to drain the horizontal one

The main rad drain point will drain the system.
The horizontal rad maybe an A/C one, crimped and bolted hoses will let you know, otherwise just pop a hose off to drain it.

At the end of the horizontal radiator facing the rear of the van, there should be a drain plug. I just checked on mine and there is one.

From memory, the horizontal radiator holds about 1.5 litres and the main one about 6 litres. The system is about 13 litres.

As stated earlier I drained the system by drain/fill with clean water/heat engine to open thermostat & heaters on/ drain/ fill with clean water etc. Effectively cleaning by dilution each time.

Thanks for all your advice.

I drained the system, refilled with water, took it for a blat around the block, and it overheated.

Drained it again, same problem.

I removed the thermostat (which is probably the most horrid thing I have ever had to do on any of my cars) and refilled the system.

Still, it overheated.

By this point, I was ready to set the bloody thing alight, and roast marshmallows on it.

As the bottom hose is in the most mongrel spot imaginable, i decided to use the top hose for my experiment.

I disconnected the radiator hose from the engine, and jammed the garden hose into it, so it had a constant flow of clean water, then let it idle away for a few minutes.

The ground under the van looked like someone had lost their lunch, but it was looking like the engine was getting a nice flush out..... then the water stopped coming out.

I thought "hang on, thats not right, maybe i should make the water pump spin a little faster" so I gave it a rev.

What happened next is something i wish to forget, but I thought I would share it with you lot anyway.

There was a sludge build-up that came out with great force, and splattered all over the radiator, and the fan, which in turn, coated the roof lining, dash, windows, and front carpets.

That (luckily for the van) fixed the problem, and it now doesnt overheat, but i do not advise that method to anyone who values their interior

That sounds to me that there was some radiator leak stuff put in at sometime.

The interior needed a good clean anyway did it not?

I was told by a radiator repairer that mixing green and red coolant can create sludge.

yes, it did need a clean lol (needs it more than ever now though)