VZ running hot every trip

[exanVZ]

Hey guys,

I'm new around here so hi to everyone I've had my license about 6 months and bought a VZ as my first car. It's been great since I got it, loving the car, but in the last week or so I've run into a problem. After a few minutes of driving the temp gauge slowly climbs and will get all the way up to H if I don't stop or turn the heater on to draw out some hot air. I've checked oil and cooland which both seem to be full, and were checked last service (a few months ago).

I've read the below thread (didn't want to make my first post a necro post) and think that this might be the problem, either radiator cap or thermo.
VZ V6 running hot for no apparent reason

I will try a new radiator cap tomorrow and see if that fixes it, I am sure I will be able to figure that out. Any other suggestions (before taking it to get it looked at)?

Not knowing much about engines, but wanting to learn how to take care of this car for many more years, any suggestions on where to start? Would also like to look at some minor upgrades like aftermarket filters such, but really just don't know where to start learning. I am very good with computers and electronics and can usually figure out how something works by looking at it or by taking it apart, however, not something I am keen to do to the car! Any ideas let me know

Cheers,

Patrick

[Little Red VZ Go-Kart]

Patrick, I'm sure you'll learn a lot of great interest from the JC community here, and particularly the VZ model.

But the first rule of thumb is not to play with the electronics: the VZ literally bristles with sensors that continuously feed electronics (two computers control the circus: body control module and engine control module). Great stuff for the electronically well-endowed; otherwise steer clear.

When something needs attention, the VZ-series will display an error code (Pxxxx); if the engine requires an unscheduled service somewhere, it will display a spanner and Service Vehicle Soon (abbreviated to SVS display when the message is cleared with Mode if it annoys you!) . A programmed scheduled service interval would display as 10,000km service due (set by the techies after service). Lots of other things to learn and of course trawling through the JC forum will doubtless stoke your enthusiasm, but temper it with caution: you'll also find how people have a lot of strife!!

I would suspect a faulty radiator cap as the first culprit worth looking at. If the hot condition persists, an investigation of the thermostat would be in order, plus the temperature sender. Also check the coolant reservoir level (that's the right side yellow cap at right of radiator/engine cowling on VZ engine bay) Though never experienced it myself, apparently the VZ can log a fault or trouble code regarding the high temperature situation and this can be interrogated by a Holden techie (yes, yes, often at ridiculous cost, so leave it out of preliminary searches!).

The subject of aftermarket filters is a bit of a bone of contention: Holden (and several well-research websites) will tell you they make no difference; others including the manufacturers will swear absolutely by them with often promising but largely unsubstantiated (given a huge number of variables) claims. I personally view some of the claims regarding aftermarket filters with great suspicion built on many years experience in driving very long distances and extensive servicing. Others here I'm sure will differ, and I respect that. Note that some oil-impregnated filters, often quoted as performance-enhancing/economy enhancing, can bleed oil onto the MAF sensor just before the filterbox; when this happens, erratic or retarded engine behaviour may result as the MAF sensor is sensitive to any type of surface soiling e.g. dust, oil, etc. (the MAF — mass airflow sensor — is a frail vertical wire that detects the amount and velocity of air entering the manifold snorkel from above the air filter and the information it gathers is interpolated by the engine electronics to adjust fuel-air mixture and throttle response, among other functions. BTW, don't touch it with your paws!!).

Something to get you started. For this poster, something down in the garage now needs to be started and taken for a spin, for every VZ likes to be used, of course!

[exanVZ]

Thanks for the reply Little Red VZ, I'm not talking about doing anything drastic, just slowly starting to get my own hands dirty.

I've found this guide to flush out the cooling system, if changing the radiator cap doesn't do anything, I was considering giving this a go. Looks fairly easy to follow, although it is a different model shown, is the VZ much different? If I follow this as closely as possible would I get stuck anywhere where the VZ is significantly different?
How To Flush A V6 Cooling System

[richardpalinkas]

same as above, check radiator cap and if not, the thermostat.

regarding filters etc. just buy a k&n, it will last the life of your car so it saves money there, just make sure that when u oil it up, let it sit on some abforbant towls or newspaper to absorb the excess overnight, that way you should not have problems with too much oil on the maf.

also, if you are looking for a little 'deeper' induction note, buy a 90mm pvc pipe and do a 2 hole mod, just search and you will find the answers. its easy and has a nice induction noise and possibly one of the best air inductions you can do, and with the price of it (<$5), its not money wasted lol. obviously there are other options like MACE and SS Inductions, but a lot of people swear by the 2 hole mod

[exanVZ]

Thanks for your reply too richardpalinkas, hard to get back to people when I have to wait on posts to be moderator approved, but thats hopefully just because I'm new.

Edit: Found this guide for the '2 hole' mod, looks pretty easy to follow and good pics!
http://swingtan.customer.netspace.net.au/2hole.html

Anyone else, keep the links or info coming and I will be sure to read it.

Cheers,

Patrick

[Little Red VZ Go-Kart]

A bleeding procedure (to expel air) must be followed for the VZ engine; if this is not done airlock can stop the free flow of coolant throughout the engine.

[exanVZ]

Hey guys thansks for the advice so far.

I went to supercheap after work to try and get a new radiator cap (as didn't get a chance on sunday) and the guy looked up my car and gave me a small stainless steel cap. Didn't look right but he said its what the book says and I can bring it back if its wrong and it was. Checked the engine to find a plastic screw on type. Going to have to go back tomorrow, but I hate driving around right now the way things are. I have to have the heater on full blast to keep the engine at about 80% heat. Doesn't get much hotter with the heater on max and if I stop driving temps quickly drop so I hope thats a good sign? Really sucks not having air con lately tho.

Can someone give me a run down on how to check the fluid levels in the cooling system, the only thing I know how to check is the coolant next to the air filter with the yellow cap and a dipstick, which is at 'max'? Also checked oil which is fine too. Is there anything else to check as I have read people check it by the radiator cap and top it up that way too... but how do I tell how much is in there without a dipstick? Please forgive this if its a stupid question as I don't know much about cars and this is my first. I don't have any mates into cars or a dad to ask or anything, so I am kind of on my own here. I would also like to know how to get into diagnostic mode on my cars computer? I've read that you can monitor coolant temps and such which might help diagnose the problem further. Just a link or something to some common commands would be good.

EDIT: Answered my own question about the disgnostic mode (doesn't seem to be in the cars book tho?)
"Put the key in the ignition, hold down the mode and set buttons, and turn your key to the "on" position."
Will see what this tells me on the way home from work today (less than 10 mins drive so doesn't usually get too hot, but can take it for a spin a little longer to find out!

I also got some pvc pipe today to do the 2 hole mod with MCAI on the weekend, it is so well documented even a noob like me feels confident doing it.

Will also upload pics of my car on the weekend (after a wash) as I know thats what u guys like to see. Right now its pretty stock standard except for 18's and a stereo (first port of call for me when I bought it.)

Thanks in advance.

Cheers,

Patrick

[Luke52]

lol, Supercheap.

What year is your VZ?

Most VZs have a bottle-type cap which is a regular type with a spring and round metal plate with a rubber seal on the bottom. Part number for this cap is 570-120. CPC make it, so you should be able to get it from most, if not all, Repco/Supercheap stores.

Later models had a different screw-type cap, which can only be bought genuine. GM part number for it is GM92068250.

Hopefully this saves you some trouble with incompetent SuperCheap employees. The person you dealt with mustn't have been looking at the right car, because I know for a fact that the CPC caps book has the 570-120 cap listed for a VZ V6. Trust me, not only do I work at a parts store, I've also had the joys of tracking down a new radiator cap for my VZ as well.

[exanVZ]

Thanks for the info Luke, it's an 04 VZ so what you've suggested seems right (after having looked at it yesterday) will be sure to get the right part this time.

EDIT: ok got one today from repco, the part numbers a bit different (repco brand, repackaged? looks identical) part# RC94-120
the one i got yesterday is part# 538/20 so who knows where that came from? I guess its my own fault for being dumb enough to trust the guy there.

Will report back once the engine is cool enough to change it and see if it helps.

Also ordered a MCAI for 2 hole mod, still $20 from holden dealer (metro in morley - they got lots).

Cheers,

Patrick

[Luke52]

Bingo, Repco alternative is the RC94-120 (I work at Repco)

[exanVZ]

Well I changed it over and screwed on as tight as I could (hand tight is ok yea?) but still running hot. I will let it cool right down before giving it a second chance, current perth temp still 34-35c.

I removed the old cap while the engine was still quite hot (but not too hot) and noticed the coolant was almost level with the bottom of the neck where the cap screws on (full!) and then I checked the overflow (coolant checker thing passenger side) which was almost double the 'max' level on the dipstick so could it be that there is now too much coolant? I added 2L recently when the problems started without really knowing what I was doing, could it mixed brands (I used tectaloy heavy duty 90+)? Is there an easy way to drain some out (if there is such a thing as too much) so that I can test it with regular levels?

Temps are still getting hot, over 120c (turned on diagnostic to test) but within a minute of turning on the hot air it drops to 112-115ish (3/4 between C & H) where it will sit as long as the hot air is on. Seems to me it is just getting a little too hot.

If it was a thermo getting stuck, temps wouldnt behave so consistently (i think...) and there are no leaks visible and not a drop has hit my carport since I bought this car (7 months+) so I am pretty sure that it can't be a leak either. Again oil is okay too (that I do know how to check).

Any suggestions before forking out to get this looked at? Seriously can't afford that right now. Really appreciate the advice everyone, keep it coming!

As a last alternative, anyone who knows what they're doing wanna take a look for a carton or mates rates or something?

Cheers,

Patrick

[Luke52]

The only coolant I'd use in an Alloytec is the Nulon long-life red coolant. Matches the GM 6277M specifications.

It's not good to mix colours, either. The coolant you used to top it up would have been green, right? Do you know what colour the coolant already in the system was?

After I had some heating/cooling issues, I got the cooling system flushed and had the coolant replaced. That was just for my peace of mind, really. Plus the "coolant" in the engine looked clear, so I'm pretty sure it only had water in it since I bought it...

But now I know exactly what's in it, and that it's good coolant matching the right specifications.

I'd definitely get it looked at ASAP mate. I know I'd rather replace a thermostat than a pair of head gaskets.

[exanVZ]

Thanks Luke if I change it i'll go the red coolant for alloytechs.

I did the 2 hole mod today as I had some time. Engine runs a bit more rough at the idle but goes a lot smoother on take off. I assume needs to get used to being able to breathe now.

I also bled some air out of the cooling system using the coke bottle method, all the coolant both under the rad cap and out of the bleed valve was green, so I assume what was in there before was green. I doubt 2L of green could make much difference in colour if it was all red. Let it get real hot then cool a bit, did it again but no air came out so should be okay there.

Felt the temps on the hoses as I heard thats also a good way to tell if everythings working okay, top hose quite hot to touch, bottom hose warm but not too hot to touch.

Rang a local mechanic today who suggested taking it to natrad for a radiator clean, rang natrad who suggested taking it to a mechanic to get the thermostat checked.
Haven't booked it in anywhere yet.

Kind of at a loss as to what to do as I can't really see any faults, other than running hot.

Cheers,

Patrick

[imoore]

if the cooling system has a mixture of green and red it can cause an engine to over heat. if left long enough it will turn to a jelly blocking radiator and water jacket. if like you say it has been mixed id recommend you take it to a engine cooling specialist and get them to flush it out asap

Ian

[exanVZ]

Thanks Ian, I'm going to take it to Natrad this week coming as soon as I get the chance. I am not sure if it has mixed or not, but I think its out of my league to fix so going to get the experts to take a look. Will come back and let you all know how I go in case anyone else has a simillar issue.

Cheers,

Patrick

[Luke52]

As I said before, if you're replacing the coolant, use the Nulon long-life red stuff at 50/50.

[bigdaddycool]

I've had this issue a few times on my car..........

1. Check engine oil on flat surface, be sure to check the stick two or three times.
A. When the car is cold, take the coolant cap off (make sure u see coolant).
B. Bleed the coolant (a must on these cars!)

* To bleed the coolant. When the car is cold, take off the coolant cap, start the car and let it run for 10 minutes with the cap off (you will notice air-bubbles coming out). Top up the coolant, repeat (but only do this when the car is cold, as the car gets hotter the coolant will being to rise, get hotter, flow.....) If you let it get too hot you could damage the engine or your water pump.

It's a safe thing to do, just takes practice. Do it once, top it up, repeat once or twice within the next week and she should be right.

[exanVZ]

Thanks guys, I had it looked at by Natrad this morning and within about 15 minutes they confirmed that the fault is thermostat. Any ideas how much I am going to be looking at to get it replaced? Not a job im confortable doing myself. I'd just like a ballpark figure so I don't get ripped off.

Cheers,

Patrick

[exanVZ]

well getting the thermostat replaced today. will see how it goes after that.
have also asked the mechanic to give me a heads up on any preventative maintenance it might be worthwhile to perform while he has things in pieces (eg. plugs)

thanks for the advice recieved here so far

[exanVZ]

Thermostat changed yesterday, and car has been running well since. Hasn't risen above 1/4 on the temp gauge.

The mechanic who did it hasn't done a VZ before mine, and said they are a real pain in the ass, but also mentioned that the alloytech engine was made for the front wheel drive cars in the US which usually results in the engine being positioned differently, and the thermostat not being so difficult to reach. Probably one of the stupidest decisions holden could have made for this car.

Glad it is sorted now anyway.

Patrick

[Phyco]

also mentioned that the alloytech engine was made for the front wheel drive cars in the US which usually results in the engine being positioned differently

Not quite the case, "Holden had the job of developing smaller engines (Holden 3.2, LP1 and LP9 Turbo) as well as their own Holden 3.6 HFV6 (called the Alloytec V6) for local models." so they were designed to be used in RWD vehicles. Holden just like to be difficult Glad your issue is sorted regardless, now you can focus on mods rather than repairs.