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engine cooling


khughes

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Okay, on to my next problem :D

The car is now idleing well, and managed to drive it 35km today without it dying once (that alone is an achievement!). The car is an Auto.

Apart from some over-fuelling issues (the carb is totally full, the float is up, but it hasn't stopped the fuel from flooding the carb, i am running the stock fuel pump, and an inline 5-7psi electric pump, the guy said it wouldn't make a difference seeing as i needed 4psi)

The problem i am now getting is the car is overheating, when i say overheating, it is right up to the last mark on the temp guage before it hits 130.. The scary thing is.. this is happening when driving at 100km/h on a freeway!

I have previously flushed the radiator a number fo times with water, and recently with nissan radiator flush fluid. It is now filled with new radiator fluid. What has me worried is that i have an oil cooler that i need to install, which will partially cover the radiator.

I assume this isn't normal, so how can i go about reducing the temperature? This is winter in sydney, it is not going to last out in the desert in october!

I was thinking of maybe:

- Installing a thermo fan on the front to suck more air in (but really, how much air does it need, i am doing 100km/h!

- installing an Auto transmission cooler (this should take some heat soak off the radiator, but again, as realestate is pretty tight, it may take some radiator space!)

- maybe the water pump isn't working effectively?

I also have another radiator, which is from a manual, but it looks to be off a z or something, although similar in dimensions, it doesn't have the drain plug at the bottom, like it does on my K.

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Have you considered that the sender unit may have gone u/s or faulty.

I had a similar problem in the 240, this was traced to a faulty transmitter. Swapped it out with a used one, stilll reads high but that may be due to gunk left behind.

Otherwise, is the termostat functioning correctly?

HIH

MOM

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Not familar with the 240k but should be one of only a few things. When you flushed the radiator did the fuild come out brown or off color or was it flowing like mud? A visual check from that as well as checking the radiator from the cap should give you an ideal if the core is corroded. The cheapest way to start is a new thermostat. Or you can test yours by removing it and boiling it in water to the determined release temprature and see if it is working to begin with. Usually when a water pump fails either the bearings inside start making a grinding or squeal noise , they also have a tendency to leak water when failing with the extra pressure on the shaft. If the water from the flush was very dirty or slush like you could also have clogged up some or your water paths in the head or in a sharp bent in a narrow pipe. Being that the car overheats when driving I suspect its not getting water movement so I probably would bet the fan clutch is fine < in the 240k has one> .

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yeah, the thermostat had already been removed, so it can not be that.

The radiator did have a fair bit of crud and off coloured muddy water in it, but after a few flushes this pretty much stopped.. i assume that it is actually getting pretty hot as when i was running the car with water only in the radiator, after the car got up to operating temporature, the level of water had dropped, presumabely it had boiled off.

but i wonder if your right about the radiator being stuffed internally due to rust etc.

yep, the fan is spinning all right.

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well attach a catch can to the overflow hose of the radiator that way you can tell if it boiling out, while you are driving . But if you are running a 30% antifreeze / boil and 70% water you shouldn't have any boil away unless its leaving the system. I would try flushing the car with the motor running just leave the bottom radiator hose off and plug up the bottom on the radiator and fill. I would quickly replace the water with antifreeze to prevent any rust issues. Does it overheat with it idleing?

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Aint these older cars fun? It may be worth getting cooling system radiator and engine proffessionally "flushed". More $$ hahaha......weep.

If old radiators have been left sitting dry for even a short period they can get gunked up internally and not work well.

Is the "air shroud" still in place? it is important to have the air actually moving thu the radiaotor so it can carry the heat away - the shroud ensures this happens rather than air spilling out, over and around the radiator.......this is more important at low speeds when fan is pulling air through radiator

You were talking about a test run to Yass? or have I missunderstood (again) if you get to yass you are welcome to have radiator out of out spares car it is an auto unit and looks to have been recently reconditioned..well the the paint is shiney I am easily pleased.. When I last drove car late last year from CBR to Mmbatemen it cooled fine and used no water. It is waiting in Murrumbateman just a few ks from Yass...For anyone else 2500$ ( = entytry fee Gret Esacpe) for you .. free. F me! Im a nice bloke.

leon

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As for the water disapearing, i assume that was only because i was running water in it, as oppose to anti-freeze which i am now running (as of the weekend, previous to this, the car wasn't driven very far). i will check tonight to see if we are still loosing fluid, i did notice a small seeping of coolant on the top of the radiator, looks like a 3mm hairline crack.. so maybe the radiator is fubared.. at idle, it gets to about 1/2 way on the guage.

The radiator shroud is all there, i guess i will see if the coolant has been discoloured

Thanks Leon,

we are travelling up to yass and staying over night on the 27/9 (so more of a day early, than a test run!).. I guess if we don't sort the issue out by then (or a new radiator is needed), we can nurse the car up to yass (stop every 50km if need be! and do a quick F1 style pitstop that afternoon :D

i assume your heading up to albury on the 28th? we should meet up and head to albury together from yass anyway (assuming the thing hasn't carked it by then!

can't wait to see what is next!

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yeah, the thermostat had already been removed, so it can not be that............

When did you remove the thermostat? Did you have a cooling problem before you removed it? There is a recent thread about thermostats and what temperature they should be. We kind of disagreed on that point but the consesus is that you do need to have one in order for the engine to properly cool. http://www.classiczcars.com/forums/showthread.php?t=18373

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the thermostat was missing when i bought the car, we had pulled it apart to test, but found that it doesn't have one.. the car had been sitting in a field for the past 7 years

will check out the thread, but i would have thought that the thermostat would have helped to get the temperature up to start with and then would have been a restriction to flow otherwise.. but i guess i will find out :D

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......... but i would have thought that the thermostat would have helped to get the temperature up to start with and then would have been a restriction to flow otherwise......

The flow needs that restriction so that the coolant doesn't move too quickly through the radiator to be properly cooled. (you'll see that in the thread)

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Also:

The thermostat helps keep up pressure, to distribute flow evenly through the head - very important.

If it's overheating at 100km/h, then you have a problem. You're only using 20-30kW at this speed, and the airflow through the radiator is better than any electric fan could ever hope for.

My bet is the radiator is blocked enough to stop it working. I had the same problem on my 1600 - it ran very hot at 100km/h, despite repeated flushes. I put a new radiator in it, and it never looked like getting hot again.

If your carby is overfilling, it's probably your float valve seat. Either the seat has some gunk on it, or has worn out/ corroded, preventing it from sealing off. You DO NOT need the mechanical pump in line with the electri pump. Run the mechanical pump inlet hose directly to the carby. DO IT, NOW!!! :classic:

The water can't boil out of the radiator. If it does boil, the steam will still escape through the radiator cap. Putting in an overflow reservoir will show you whether this is what's happening.

Hope this helps.

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