** Up front I would like to thank everyone who takes the time and effort to read, and I'm even more grateful to those who reply ** Motive: I was blasting around 200kp/h for a few minutes and monitoring the gauges closely. Oil was at a steady 100c.. upper radiator hose temp was steady around 80-85.. however. Normally this was never a problem. However this apparent (hot) day, slowly the engine's water temperature (measured just before the thermostat, on top) started going into 3/4 (~ 105c est.) so I eased off and it went back to normal. Odd. Facts: Stage II CA18 Oiltemp is fine and sensor is precise, tested it with a waterboiler. Upper coolant hose is fine and sensor is precise, tested it with a waterboiler. No det going on, at least no noticeable. Ambient temp was 32c Last year did 20 laps NS in 30-33c temps, no problems whatsoever. Thought 1: So the upper radiator hose temperature is fine.. that should mean the engine temp is fine as well..or is it? Question 1 Does water circulate like; from being sucked in through the lower hose into the engine.. circulating the engine.. and spit out through the upper hose to be cooled off by the rad and sucked in at the lower hose again? I initially thought this, but a friend who has a Camaro told me it's the other way around (sucked in at the top). If the latter is the case, it explains why the engine is hot but the upper hose is not as hot (as it is cooled coolant). So what way does it circulate? Thought 2: The cooling system is a closed one, however the expansion tank is missing, so I made a catch tank for excess coolant which sits near the chassis beam down low and has a small vent for air pressure release on top, so no coolant can get out. Question 2: Now I wonder.. if the coolant gets expelled to the catch tank, the water evaporates partly and Glycol stays behind (having a lower evaporation rate I think) and gets sucked back in. From time to time I have to fill the radiator back up with about 50ml or so. This means, less water, more Glycol. Water is the best cooling agent there is, so can it be that I am losing cooling ability? Sub-question, I have the cheapest coolant there is in there, but I got told there is (like in oil) a quality matter in coolant too, especially German OEM one being the best, is this true?
Youre funny as fuck Vova, you overthink things too much. The circuit flows from pump > block > head > thermostat > radiator then back to the pump. So the stock gauge increased temp but an aftermarket gauge stayed normal? I would guess its an airlock. I've had it happen to mine when I havent bled it properly and the dash temp gauge changes with load on the engine. Has your thermostat got a jiggle pin and hole? maybe its caused by your overflow tank arrangement allowing the radiator to suck air in? If that doesnt fix it then maybe your thermostat is playing up as thats the only thing between the two sensors. Oh, also check the connection on the stock sensor, they can get corroded and make the gauge do odd things.
A jiggle pin? WTH is that? I doubt it is air, I had the temp sensor out and filled up the rad, no air came out. Then let it run with the cap off, no bubbles. I'll recheck the sensor (even though I cleaned it) and maybe change the stat (even though it is only 15k old..). Hmm, so the flow is like I thought, from top to bottom. Thnx Steve
to answer: usually hot water goes in the top of the radiator, cooler water comes out the bottom and cools the engine, it's working with the natural tendencies of the fluid (cool stuff is denser and sinks, hot stuff is less dense and rises). Older (vintage) used to use a "thermo-syphon" effect without a water pump, which is why old cars have tall radiators. Modern cars do it to a lesser degree and continue to circulate coolant around the block after the engine/pump's are switched off There are probably some exceptions to the rule (can't think of any off the top of my head) For your second q) you can increase the amount of heat the coolant system can store by raising it's pressure (as pressure rises the boiling point goes up, as it goes down, boiling point lowers, which is why i't shard to make cups of tea up mountains), the greater the difference between coolant and ambient temps, the more heat can be removed, also painting the radiator matt black can help lose an extra degree or two. Worthwhile flushing the radiator and the block etc. Additives: Water wetter and glycol - glycol reduces the freezing point, water wetter stops the block/head from corroding (which can subsequently block the radiator) Expansion tank: your pressure cap has a relief valve, as the pressure goes beyond that, it spills out into the expansion tank, as it cools down, it should suck it back in, so you ought not need to top it up if everything's working fine. If you're temps are rising and were previously good, flush and clean and don't use straight water (I know some tracks want cars/bikes to use straight water because it's not as greasey as glycol if it spills) if your losing water, then there's a chance you've got a bigger problem (do a sniff test for HG failure and check your water pipes for leaks/cracks)
Wow, epic reply majic! - Sounds like sense, from top to bottom. - So I can use water + water wetter + some glycol for a perfect coolant mixture? - My improvised expansion/catch-tank sits near the lower chassis leg. Could it be that the height difference (i.e. gravity) prevents it from being sucked back in (enough) ? Making me fill up a quarter cup every 3 or 4 weeks? - The HG is fine, did a test after replacing it with a Cometic one. - Been advised to flush the system indeed, might give that a go and replace the current coolant with gooed OEM German one. What is the best method to flush? Again, thanks for the help, awesum
Jiggle pin..... Its a hole at the top of the stat to prevent airlocks. The pin in it is to stop the hole getting blocked up by crud, by jiggling around in the hole.
There is no perfect mix Glycol lowers the freezing point, but also lowers the boiling point, most additives lower the boiling point (which is one of the reasons pressure caps are fitted), but you need something to try and stop the block/head corroding. We used to fill the system with a glycol based system over winter, then in the racing season, drain, clean and fill with pure water. End of season, flush, drain, refill with glycol based. To flush it, disconnect your rads top and bottom hoses, remove the radiator, turn it upside down and back flush with a hose pipe (flush from the bottom pipe and out the top), flush the block using a hosepipe the the 'stat removed, hosepipe in the top elbow, let it wash out the bottom hose. I know there's several types of coolant (and they usually include anti-corrosion compounds as well as glycol), always go for the type recommended by the manufacturer, I'm used to running toyota engines, and they have (had) the "4-life" coolant. If you've got alloy and iron/steel mixed, there's one type of coolant to use, another if it's all iron and I think for dry/damp lined alloy engines yet another. I think the CA's are iron block with alloy head, so the toyota style coolant should do the job, just make sure whatever you pick up is suitable for the type of engine
Many thanks guys, I think .. no I AM going to do the following: 1. Remove thermostat en check, and check the jighole or whatever 2. Drain all coolant 3. Remove rad and flush 4. Fit a OEM expansion tank where it was OEM'lly 5. Fill with Alloyhead-Iron block German coolant 6. Cross fingers Again, DW FTMFW!!! Thanks guys, really apreciate, kisses and hugs XXX /edit: Turn 2 and 1 around might be handier me thinks
