overheating

[235rwkw]

well got me beat this one, asked elsewhere but no answer or help, trying here maybe someones had this problem.
cars running up to 15 deg hotter than normal. runs at 85 deg almost always except in traffic, where it will go up but come down to 85 fast with the fans on, and run at 85 on the hwy. but now really struggles to get below 95degs, fans on, driving over 60, no power used, should bring down the temp but its not, downhill runs still staying up.

it not the radiator, it doesn't use coolant, its not the thermostat, the cap holds pressure.

whats is causing the increase in temp? seems to be getting worse.

i've put in another stat but its not the problem had the stat test boiling for over an hour it held wide open both the new and old one.

[scat2k3]

I had a very similar problem recently. It turned out to be a sheet of plastic that was up underneath the deflector plate for the OTR I was running. This effectively blocked off 1/3 of the radiator. You couldn't see the plastic from above, and it wasn't until the car was on a hoist and you looked up that it was found. Car would run fine but about 15 to 20 degrees hotter.

Might seem obvious, but make sure there are no obstructions before taking further action.

Cheers,

Scott

[235rwkw]

I had a very similar problem recently. It turned out to be a sheet of plastic that was up underneath the deflector plate for the OTR I was running. This effectively blocked off 1/3 of the radiator. You couldn't see the plastic from above, and it wasn't until the car was on a hoist and you looked up that it was found. Car would run fine but about 15 to 20 degrees hotter.

Might seem obvious, but make sure there are no obstructions before taking further action.

Cheers,

Scott


thanks but not that had the radiator out and cleaned and put back a few days ago, but wasn't that its still doing it. would have seen any crap then. the week before that had the front bar off for the cooler

it did get a little worse when i put a auto cooler in, that was an attemp to fix the problem also, but it didn't help either thought taking the load of the radiaor would helop, made it a tiny bit worse. seems to be a flow problem but isn't as far as i can tell, fluid or air.

PS i know how to make connetors for the cooler lines nowe without cutting anything all screw up connections

[RedVYIISS]

are your radiator fans cutting in when they should?

[eraser]

yep thats what id be looking at. Get a laptop plugged into it to check the fans operations

[Brockfan05]

Did you put new coolant in, or re-use the original stuff? Coolant has a shelf life as well as a limited operational life, new coolant could make a difference maybe......other than that - no idea?

[235rwkw]

are your radiator fans cutting in when they should?

that?s the next problem (really an old one still not solved), not a real problem as such. It doesn't affect this temp problem, as i can switch them on when required. If the air cond isn't on, hitting it on and off will run the fans for 30 secs or leave it on as long as required when temp comes up. the fan problem is the BCM i think, they come on whenever, dead cold, 40 deg, 50 deg, 85 deg 95 deg whenever they feel like it. even sometimes when i go over a bump they come on. Fans have been a problem for a while now, longer than the overheat prob. i can't find a short to earth, its not the relay, must be within the fans or the bcm, it a low speed fan prob. the fan prob is they are on TOO MUCH when they shouldn't be.

Did you put new coolant in, or re-use the original stuff? Coolant has a shelf life as well as a limited operational life, new coolant could make a difference maybe......

the coolant was less than a year old, but i put new stuff in anyway. The coolant is about 3 years or 90,000 k's stuff. but i never believed that should be the case and change it more often. Talking to the radiator guy who cleaned it out and replaced a tank. he said yearly because they still build deposits which can block the radiator. and i sorta believe that because mine has been changed and still had a 20% blockage of deposits.


I think i know what the heating problem is now. car was much cooler today but that was only a short trip to work, i need a bit more driving to confirm if its fixed and what it was.

then back to the fan one, i hate electrical ones. (a pain when you want the car to warm up and the fans are running when cold, like when testing the radiator install for leaks before driving, i pulled the relay when they came on for this)

[235rwkw]

nope still don't know still need help.

went for a longer driver and the further you go the worse it gets. temps up and down gradually gets hotter and hotter and the temp doesn't want to come down taking longer.

the temp variation keep climbing around a higher and higher point.

anyone know if a water pump can cuase heating probs like this?

[SSUte01]

I am just thinking out loud here, so stick with me

- Fans definitely working albeit not when they are supposed to - check
- T-Stat confirmed to be opening etc - check
- Coolant levels/Coolant adequate and no leaks - check

More questions:

- Is the top radiator hose v.hot like the bottom ie does the water appear to be circulating

Absoultely a dodgy water pump will cause issues.

- Oil is still nice a oil-like, no traces of water ie milky/grey (although this should be answered by no loss of coolant) - This is obviously worst case and not likely

- BTW the fan operation is controlled by the PCM, series/parallel, on/off at whatever temp as well as a low speed disable speed (that is what the air is for at speed)

If water is not circulating as designed and relatively stagnant it 'could' be the issue. Hard to diagnose from here however.

- Is there any excess play (slack) in the water pump or any evidence of wear - grasping at straws here.

See what you can find out.

Also, what was your suspicion, since disproved.

Luke :)

[235rwkw]

I am just thinking out loud here, so stick with me

- Fans definitely working albeit not when they are supposed to - check
- T-Stat confirmed to be opening etc - check
- Coolant levels/Coolant adequate and no leaks - check
-radiator cleaned out and flow checked - check

More questions:

- Is the top radiator hose v.hot like the bottom ie does the water appear to be circulating it appears to be.. trouble with these early setups can't see the flow

Absoultely a dodgy water pump will cause issues. they leak, they have bearing issues i can't place in my head how it would not be pumping if its turning ules the shaft is loose inside, have seen older style pump run a little hot with bad bearings, extra heat into the coolant

- Oil is still nice a oil-like, no traces of water ie milky/grey (although this should be answered by no loss of coolant) - This is obviously worst case and not likely no oil is ok normal

- BTW the fan operation is controlled by the PCM, series/parallel, on/off at whatever temp as well as a low speed disable speed (that is what the air is for at speed) almost high speed fan is controlled by the pcm, low speed by the BCM also as it strart them for the air cond etc

If water is not circulating as designed and relatively stagnant it 'could' be the issue. Hard to diagnose from here however.

- Is there any excess play (slack) in the water pump or any evidence of wear - grasping at straws here. no seem to have no slack, spins fairly smoothly too, no noise. it is 130,000 old however the impeller is to far inside to see it without removal

See what you can find out.

Also, what was your suspicion, since disproved.

i remembered i modified the stat to open sooner giving me the 85 deg temp, iso i modified the new one to open even sooner, it helped extend some time back but its soon overcome by whatever is causing the increase

Luke :)
answers in colour...
what changes the longer you drive, what can be effected by gradual heating to cause a flow restriction when exposed to normal temp for a period of time. i can't think what could be going on. its like a flow restriction or air flow restriction but only when hot for a while.

the really weird thing is the sunday night one when it ran at 70-75 degs for 15 mins, its never run that cold before. but then climbed up above the normal 85 deg to 95 -100. its run ok at 85 for 2 years until now, its gradually got worse, more so more quickly recently (last month), it got worse after the tranny cooler install 2 weeks ago and worse still after the reco of the radiator last saturday, both supposed to fix the problem.
a long time back, just to get perspective, on the 85 deg the temp was normal over 60 kph say, slower periods or stop start it would go up slowly, but then quickly reduce when the fans come on or you got back to speed.

now at first i can see a reduction with the fans but that bcomes less the longer you drive, to a point with the fans on its sitting on 98 degs just cruising at lowest, give it some it get worse now. 3 weeks ago it hwy speed the temp was ok, but worse lower speeds, my average temps increasing and recovery is becoming almost non exsistant sooner. at this rate i'll be over 100 with no reduction soon.

i need a pressure test, it has pressure in that you can here it when the cap is removed, the cap mmmm another thing i guess. but a recall one day a long time ago forgetting to put the cap on driving for 1/2 hour with no temp problems.

[seldo]

You seem to have done most things.
Many years ago we had a similar problem with a Rover SD1. They tried everything.......and then I found that someone had plugged the fan-wiring in back-to-front, so that the polarity was reversed. What this means is the fans blow forward instead of sucking back....:shock: It also means that the hotter it gets, the more the problem happens as it can't disperse the residual heat.
I'd check it... ;)

[235rwkw]

i'll relook at that, but the fan wiring plugs can only be plugged in one way, plus they do have a cooling effect when on for a while bring the temp down the first few times from over 90, but then after that less and less so.

[BLK 1T]

OK if I have have to take a guess we are all getting desperate.

Im not familiar with the internals of an LS1 water pump but how does this sound?
What if the water pump impeller was loose on the drive shaft, not enough to rattle around but enough so it didnt pump enough coolant? This would happen more under acceleration as the belt speed was increasing and could be less so at idle.
Along the same lines would be corroded/broken impeller vanes.

Phil

[235rwkw]

OK if I have have to take a guess we are all getting desperate.

Im not familiar with the internals of an LS1 water pump but how does this sound?
What if the water pump impeller was loose on the drive shaft, not enough to rattle around but enough so it didnt pump enough coolant? This would happen more under acceleration as the belt speed was increasing and could be less so at idle.
Along the same lines would be corroded/broken impeller vanes.

Phil

thanks phil, i've had that thought too, could get loose when hot for a while, no way to tell without removing it either, that means radiator and everything back out again a sad thought esp if its not it.

i now know these cars have two coolant sensors one for the gauge and one for the pcm! and i have a pcm output gauge, which is why i know the temp exactly. both the pcm and dash gauge are doing the same thing approx, so cannot be a faulty sender.

thanks for the help everyone so far i need ideas. the other forum after all my years of helping others has not been much help to me this time. i'm sure some techo has seen something similiar before, hopefully i'm not the only one to have this.

[seldo]

i'll relook at that, but the fan wiring plugs can only be plugged in one way, plus they do have a cooling effect when on for a while bring the temp down the first few times from over 90, but then after that less and less so.
I thought that may be the case, but you'll also get the same problem if the fan has been taken off the shaft and put on backwards... Also, at low speed you will still get some cooling, but as the speed increases the fan can't overcome the airflow through the radiator and stalls.
The easist way to check of course is to turn the fans on without the engine running and just hold your hand in front of them. Also, check that the fans themselves are not slipping their drive-shafts. Also, maybe one is dying after a bit of use and then re-boots again when it cools down. I assume there are 2 fans? - I've never even looked...

[235rwkw]

were back again, how long for?



fans are a set of 2 on a bracket assembly, been off the radiator but not off the assembly. they work make a racket and suck air.



When i rang the Holden parts the other day they said which sensor, they have two, which is why i discounted that. However i looked at my workshop manual in the cooling section at say on one sensor, which goes to the pcm then to the dash, not two separate sensors. those guys suck...i never come across two on an ls1 before.



So I?ve order one and will try that as the next cheapest option.



since the forums been down I?ve got a new cap, no change. Tested the holding pressure of the system, made my own pressure tester :up2sum: held 10 psi easy for 20 mins. been back to the radiator guy for a look he reckons its ok, try a new stat again. Thought after nah is bloody tested 3 times and works. i have 3 atm one new, 2 old. the two old ones open before the new one, and close after, so they are cool i can't see it could be them. new one is still out, gave it another test last night to the other one still out, same story old one open first, opens wider, and for longer on cool down, so in theory should run colder.

[235rwkw]

not got the sender yet, should be in today.

But it funny yesterday arvo and this morning it hasn't been too bad, not sure if its fixed itself, or something I?ve done has fixed it recently.

I?ve discovered that since Saturday, after the new radiator went in the fans appear to be working normally, that is they are not turning on any old time like they have for a long time over a year maybe two I forget now. I think after I frigged around with the relay to stop the fans a few times, while they were going when cold, and me trying to warm it up, bloody fans. (PS no its not the relay for the fans, in the past tried a new one to fix the on too much but no luck).

So now they are not turning on until 97deg atm it seems, but were before last sat! It still taking about 10-15mins to get to the point of over my normal temp with speeds of under 70 kph from cold. then getting up to the high 90's temp and bouncing around in the 90's, with the fans going on and off normally now i guess.

So today when it got into the 90's I turned on the air cond and left it on so the fans were on all the time. the temp dropped & stayed at 85 or just below. So I think the problem maybe fixed. but I?ve thought i still had a problem because the fans were no longer running too much like before, like they have for so long now before this new problem started. But I only drove another 3-4 mins like this before arriving at work, so who knows.

The only thing is with this fan idea is even last Sunday on the trip to airport if I left the fans on ( air cond) it never came down to 85 deg, never below 90 odd, but it is now. Since then I?ve only had the stat back out and back in and added a new cap. But testing the old cap to the new cap they are both the same in operation and holding pressure.

I just need some more days running around to see what?s what I think. See if it?s really gone with some longer trips. then get the ?turn on temp? of the fans lowered if they remain fixed (fixed themselves weird, I?m sure that will come back)

I hope its gone, time will tell?..

[BLK 1T]

thanks phil, i've had that thought too, could get loose when hot for a while, no way to tell without removing it either, that means radiator and everything back out again a sad thought esp if its not it

Mate, I never said it would easy. Would be handy to have a new there to compare and return the new one if you dont need it.

I gotta say from your recent posts I am now totally lost (not difficult).

Phil

[235rwkw]

so am i lol

to much info yeah i thought that. if i give to much info its too much to read and daily updates of my thoughts etc yeah too much info....to much time too read and follow it all....

hopefully i'm getting a new pump. its a good price so if its not that it doesn't matter so much. as my pump will go sometime soon anyway ,its latest longer than most pumps ever do so i need a spare. may as well fit it anyway if the deal goes through.

[235rwkw]

new pump is in now. only been for a short leak test drive so far.

new pump has a different stat design so can't use the older designed lower temp stats in it.

As expected it ran at 89/90 deg and was stable, with the new type oem stat in it. i need to go for a longer drive to see if it remains stable over 1/2 hour driving, which is where i was having it go crazy before.

[BLK 1T]

So how did the old pump look - any obvious problems?

Phil

[235rwkw]

old pump looked OK. no bearing slack, nice smooth turning, removed back cover looked good in there too.

beats me maybe the pump, maybe the stat.


went for the longer drive at 100kph, just sits on 89 deg 88 on downhill runs, 90 uphill. back in traffic get a little higher but quickly drop down as it should when going again, doesn't stay up there.

just need to find an 180deg stat that fits this later pump now. one place in the states have them, rather get local if poss. the later pumps have a seperate stat to the stat housing, the stat has the rubber seal around it which seals the housing up. the older stats with housing won't fit into the new pump too big for the hole. so couldn't test that seperatly had to make 2 changes at once....