Hey guys, I have had overheating issues for the past several months, have been told all different things from diffrent shops - Radiator has been removed and cleaned , new radiator cap (twice), plenum pull was done, hoses are all in good condition, radiator has been flushed and burped several times so below is a video i took today, the tube is in the bleeder valve at the top of the radiator. it has water in it and the system has been ran for about 30mins with the heater on. when I give it a rev a get small to large bubbles coming up, Note that there does not seem to be any of the red-coloured water that videos show C02 gases to make. Also there is no steam or smoke from the exhaust - I hold a piece of paper to it and give some throttle and could still print with the paper. The car seems to run great, until it overheats. Can anyone assuredly tell me that this is a blown or cracked head gasket/head? Youtube Link https://www.youtube.com/watch?v=Kdiuf6Piq6c&feature=youtu.be
More information required! All you've stated is there is an overheating issue. How do you know it's overheating? How long can you drive it before it overheats? If a head gasket was blown, the engine would more than likely be misfiring. Also, the defective cylinder would pressurise the cooling system, therefore you'd expect to see major coolant loss via the overflow bottle. Get the engine to operating temperature & then do an engine compression test. It doesn't appear you have the right mix of antifreeze in your system either.
Run a diagnostics test ie: conzult and see what the temp says on that, how high up is your temp gauge showing in the car ( not that it is that accurate ) but if it doesn't get past 1/2 way, then it's not really overheating, but a proper temp test will be best. Plus a half an hour of sitting still with a motor running will always make a car seem to run a bit hotter.
Completely unrelated but you can rev the engine via the throttle cable on top of the engine, save you having to go to the pedal in the car when your filming
Doubt it's head gasket, bubbles are too big. I'd say you've still got air in the system. But it's only $90 or so for a chemical tester from repco to confirm whether you've got co2 in the cooling system.
Ok thanks for all the replies; In terms of overheating it has varied between the times ive taken it into the shops ( several times). But to keep it short, One day the car stalled when i was coming off the freeway pulled over , smoke came out of dipstick and oil filler, engine was very hot. took it to shop paid 4k to get a wide array of work done to it. was told it was fixed, after this I drove it for 45 mins and then temp gauge went sky high and the coolant started boiling. so back to the shops a few times same issue, was told it was head gasket, the pressure was pushing water into overflow and not allowing it to come back so it then lost water over time and got to hot etc. months later of not really using it, I took it to a radiator place on a whim , they showed me the rad cap was faulty and fitted a new one. so took it for a drive and the temp gauge stayed right on half way, everything looked fine - then went to take off from a traffic light after 1hour drive and engine pinged, off immediately, smoke out of bonnet etc. so no good still. got it home and low water put few litres into it, so I dont know - my problem is I dont want to spend alot of money fixing it if I have a bad head cause i dont have the cash for that kinda fix. There is no antifreeze in atm as i have been flushing and burping and im not wasting money on antifreeze just to drop it. I have not been able to find anyone to do a gas test on the system yet. anyone know of someone in South East melb?
No, combustion gases (and oil) entering the cooling system and pressurising it till the hose exploded like a sausage on a bbq. The bubbles wont always be small.
If it was a head gasket, I wouldn't think you'd be able to drive it for 45 minutes or an hour before you realised it was overheating. Do an engine compression test, that'll identify whether you have a head gasket issue. Any sign of water in the engine oil? Pressure test the cooling system & radiator cap, while you're doing that make sure the hose from the filler neck to the overflow bottle is clean & clean the filler bottle. Check the thermostat. Does the electric fan work, or come on when it gets hot? Once again, you are lacking detail in your information. Spending 4K on a "wide array of work" tells us zip! Did you take the vehicle to the repairer to fix the overheating issue or something else? What did they test, change or repair relating to the overheating.
1/ the vid says you have a air-lock in the system = it hasn't been bled properly. 2/ Gyycol is an anti freeze product so don't panic about it being in the system until the issue is sorted. The issue could be one of several possibilities, its simply a case of step by step diagnosis......... so start at the front Aircon electric fan- does it activate when the aircon is switched on ? Aircon condenser- yep that "radiator" looking thing infront of the radiator, check for dead bugs/road grime etc..... it can clog the aircon condenser and that severly restricts the air flow to the radiator. Radiator- check the same as the aircon condenser, its all well and fine to have the internal part of the radiator cleaned but the external also needs to be clean. Clutch fan shroud- zed's need that shroud, they also need those plastic under trays between the front bumper and the radiator support panel..... Nissan didn't waste thousands of $$$$ in research and development for some backyarder to simply toss them aside because they know better Clutch fan- they are a common fault with age on the zeds, there's plenty of threads on them so search away for a check..... Water pump- when was it replaced last ? the pump fins DO corrode away with age and become far less efficient. Thermostat- another engine part that has a use-by date Blown head gasket- a chem check is available from most auto shops for a reasonable cost.....AutoPro/Autobarn/Supercheap etc... many service mechanics can also perform a chem check, if they cant then don't employ them !!! pinholed block or head- again the chem check will hold the answer. The likelihood its into either the air or exhaust side is slim .....BUT you will see a heavy water vapour exiting the exhaust, if its not exiting the exhaust, then check the oil dipstick for a chocolate milk looking oil :br:
Is your overfill bottle full? One car I had seen with a blown head, pushed out all the water into the over fill bottle.
Show the itemised list from the mechanic. 4k ? as in $4,000.00 for what. What kind of repair/maintenance can you do at home. If the answer is 'nothing' then you should park your Zed until that situation changes. Find a Zed mechanic next time. They are rare and need our support.
Just read the whole thread. I think you got ripped off from the mechanic. 4k for a rebuild is a bit too cheap from a mechanic. The underlying problem of the head gasket blown didn't seem like it was fixed in the first insurance. I'm convinced if it wasn't the head at first, it will be now.
we can see from the vid that there doesn't appear to be oil in the cooling system at that stage. As others have said above, ensure a good coolant bleed, water pump, thermostat and rad fan clutch are all in good order. Seems strange that none of the workshops have got this sorted, particularly after spending 4 grand! That sort of coin should have at least given you a definitive answer.
Hi guys, Thanks for all the input on here and Sorry for the lack of detail, I choose simply to not include details to save reading time as the thread was to see if anyone could tell me if the Large air bubbles are from not being bled enough or infact a Bad head gasket, I understand that it was a long shot on if anyone could tell from the video alone, the problem being the car has been to three different Mechanical shops and all have had a different opinion. I have also read that the tests from repco etc can be inaccurate which is why I havent done this option. It seems there are a few of you that want to know the Full story so I will try my best; Several Months back the car overheated in the sense that it stalled and when I Pulled over smoke came out of the engine oil filler cap and dipstick; I took it to a very reputable 300zx mechanic recommend on this forum; They informed me of a large amount of issues and we spoke on cost and settled on what we needed done - this was; Spigot Bush replaced Throttle Gaskets New inlet manifold gasket Gear shifter bushes replaced Clutch replaced Flywheel machined PCV valve replaced Cleaned throttle body Oil filter oil change Coolant flush and change new Injector plugs repalced one faulty coil pack gear box seal rear main seal Rear turbo hoses replaced Plenum pull with hoses replaced ( I am aware that several items listed are not related to the cooling issue but as to maintain accurate with costing) the bill on this came to $3200 - I was told the water leaking under the plenum was the cause for overheating. the night I picked it up after 45 mins of driving it overheated (this time the coolant boiled in the overflow and the temp gauge (in dash) went sky high). towed back to the same mechanics and was told that the radiator was the issue, the radiator was removed and cleaned (apparently had alot of sludge in the bottom). (this was another $400ish) Same thing over heats again. Back again and told unfortunately they suspect it is a bad head gasket and a new gasket and machining heads etc was starting at $5k (i did not have that kinda money after the previous ~$4k.) On all these occasions it took several litres of water in the rad afterwards; So they said that it seems to be very very small crack and lost a little water over time, so to continually top up water and drive it easy. to and from work on the days i needed it , topping water up every morning no problems at all. anything more than my work trip and would over heat; Comes to second mechanic (radiator specialist) put a funnel in the radiator gave it a rev, said you have a bad head gasket). Months passed and it was still kind of working but would overheat after 45-60 mins. bring in the new mechanic; He said the Rad Cap couldn't hold pressure (and showed me to prove it) new rad cap problem fixed. Problem not fixed overheated again smoke out of the oil filler etc and no water in the cooling system, still losing water; So this brings me to now. I have got it booked into a place to get a full gas test Today hopefully that uncovers something. Few points; In terms of repair/maintenance I know enough have been working on cars since I was little, the problem is more to do with Time / and also to a point tools. The overfill bottle does have water in it so it seems like the rad cap is not pulling the water back from the bottle which im lead to believe it should do? Fans do work. The Ac condenser is pretty rough looking a lot of fins are bent, but this wouldn't explain that every time it over heats it takes several liters of water in the Rad?
Dude, sounds like your engine farked. I wouldnt bother doing a head gasket at this point. Everythings probably warped. For the cost youll find a drop in
How is it that the reputable Zed mechanic didn't check the radiator when they were fixing the overheating (plus other things they determined were $$$$ chargeable) issues.
Is it common for the heads to crack on these motors? Could explain vanishing coolant and air in the radiator if the compression is still good on all cylinders.
