Hi everyone, Ever since i replaced my blow lower radiator hose, i've since drained the coolant and topped it up with ~50% mix of coolant and run the car in with the radiator cap off while topping it up and made sure the coolant level is alright. Here's the issue, the zed has no issues with normal driving, around town etc. The temp gauge sits normally. However, as soon as i get on the highway, or i start cruising at 80 or so (note i dont have O/D so it revs at around 3k revs or so although i've never had this issue before the hose blew) the temp gauge would shoot all the way up right below the Hot line and the auxiliary fan would kick in. After pulling aside and letting the engine cool down for a few minutes, i can hop back in (temp would be back to normal) and do city driving at normal temps again. When the engine is cooled, i can see the coolant in the radiator has gone down, level in the overflow bottle is high. Would anyone have idea what the issue is here? Havent been doing much driving in the zed since this happened and im hoping to find the issue soon. Thanks in advance!
Could be that it's not bled properly. Realised myself these can be a bugger to bleed all the air out. Get a plastic bottle that fits in the top of the radiator, get some kind of rubber grommet to seal it, cut the bottom off and keep the level about an inch above the radiator opening while you idle / rev to 3000rpm / idle / rev to 3000rpm for a good 10 minutes or more (once fully warmed up) and until you no longer see any bubbles or drops in the level for at least a few minutes, then let it cool, top up if necessary and put the rad cap back on.
I've let it get up to temp while topping it up with the radiator cap off but i didnt rev it up to 3000rpm. I'll try and bleed the system once more when i get the chance and hopefully that will solve the problem. (neighbour isnt happy about my noisy car) Thanks for the help and hopefully this is the issue.
That's what I used to do also, and same as you, every time I'd remove the cap to check when it was cold the level was always down an inch or so. You need to rev and hold it at 3000rpm (or thereabouts) several times to get all the air out of all the myriad coolant lines all over our engines.
You'll need to rev it. Also make up a bleed funnel as Shane suggested so that you are bleeding from a "high point" in the system. Bleeding it can take ages, not something to you want to rush through (unless you want to come back and do it again and again and again lol).
Also seems a wise move to have the nose of the car as high as you can get it. Seems to help. Also, make sure the heater is on flat out. E
Why did you change the Hose? May i suggest that you may have a done a head gasket and may be the cause of the overheating. i suggest a check of exhaust in the coolant. There is a liquid you add to the coolant which changes colour if exhaust gas is present in the coolant. MichaelZ
I'm sure this is not what you meant MichaelZ You don't actually add the liquid to the coolant. The test is called a TeeKay test, you can buy a kit from Repco etc. The other tests to do are a compression and a leak down test. But first do a decent bleed as described above, this is probably all that's wrong.
Alright, looks like i better drop the engine and get a new one then But in all seriousness, i revved it up today and hopefully managed to get all the air out of the system now, i didnt end up having to top up much more water, probably about 150-200mls of water minus some that over flowed. Hopefully that solves the problem.
Man no need to scare the poor guy lol -The car ran find before changing the hose -He's just dropped all the coolant from the radiator and hoses -It hasn't been bled properly Start by bleeding it correctly... Or if you have cash to burn I'm quite happy to pressure test the system and cap, TK test it, compression test it, and then tell you to bleed it...
Also states that overflow level was high, so it is expanding but not returning. Indicates somewhere is leaking air back in.
Or the caps screwed. Do the basics first man, get a new cap, bleed it as per correct procedure, make sure you have nothing blocking the airflow to the radiator. Most people have O/H problems in traffic and low speed commuting, not high speed, so it does indicate a bit of a problem. Mine used to keep cool with all fans turned off (electric) in summer at 120km/hr, i had the nismo thermostat and my engine actually ran quite cold (about 78) in summer on the freeway.
