Overheating / Temp Sender Dramas...

[jackbyo]

So my temp sensor is screwed. I went to get a new one and the guys at repco came up with a VDO part number 320.043

 

anyways turns out that part is bigger than the old one thats in the engine now.

The new part had a thread diameter of 16x1.5, where as the old one that fits is 14mm

 

the guy at repco couldn't find any temp sensor for a corolla that wasn't 16x1.5. There was a part 320.044 that someone mentioned on another thread here somewhere but it apparently has the same thread size just different ohms

 

He's ordered in one thats for an alfa, part number CTS145 that looks like it'll fit, but he doesnt know the ohms for that part or the ruined one that's in my engine now... if the ohms are different I'll get a false reading

 

so if anyone has had to fix their temp gauge and ended up with a 14x1.5mm sensor that fits, can you tell me what part number it is and maybe the ohms??

 

right now i'm driving around with the heater on full blast to get rid of some of the engine heat because I just dunno if it's running really hot or not.

 

cheers

Edited October 6, 2010 by jackbyo

[Evan G]

i got the specs somewhere, let me find em!

 

 

temp senders with the same resistance but from other car..

 

- LASER KA-KB

- METEOR GA-GB

- TELSTAR TX5

- MAZDA 323 FWD

- MADZA 626 FWD

Edited September 23, 2010 by Evan G

[Raven]

Alternatively, if you want to look at specs, check out the link below.

 

Just so you know, Tridon also list it as an M16x1.5 thread type, but under KE70, there is no listing as they list a thermo fan for some stupid reason.

 

I'll bring this up with my Tridon rep when I speak to him next and get that fixed on the website.

 

Click Here

[altezzaclub]

or fit it and put a thermometer in the radiator then let it idle until its hot.

 

As it climbs you can check the guage against the actual temperature, ideally the midpoint would be 80deg or so.

[Trev]

or fit it and put a thermometer in the radiator then let it idle until its hot.

 

As it climbs you can check the guage against the actual temperature, ideally the midpoint would be 80deg or so.

 

This, I use a laser thermometer on the cooling system (pipes, radiator, thermostat housing) to check for temp differences and range.

[philbey]

what's a good IR thermometer worth Trev? I've been thinking of getting one, if there's a 50 buck special out there that's good, let me know.

[ke70dave]

hows this one:

 

http://jaycar.com.au/productView.asp?ID=QM7219&keywords=thermometer&form=KEYWORD

 

only goes up to 220C

 

this one is $100,

 

goes to 650 apparently

 

http://jaycar.com.au/productView.asp?ID=QM7221&keywords=thermometer&form=KEYWORD

[Trev]

what's a good IR thermometer worth Trev? I've been thinking of getting one, if there's a 50 buck special out there that's good, let me know.

 

Only ever used the blue point 260c one.

 

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=77405&group_ID=1362&store=snapon-store&dir=catalog

 

There are higher temp reading one's on there though.

[jackbyo]

or fit it and put a thermometer in the radiator then let it idle until its hot.

 

As it climbs you can check the guage against the actual temperature, ideally the midpoint would be 80deg or so.

 

edit: I see that I'd have to get an optical thermometer of some sort, but where abouts do you measure from? Just point it at the block etc??

 

 

i've just done my first proper coolant change. Flushed out the radiator with a garden hose in the top while the bottom radiator hose was off until everything came out clean. pulled that block drain nut off and drained that too. Put fresh coolant in and it's gone straight to hot still...

the radiator cap feels cool to touch, and the coolant doesnt appear to be moving from the reservoir but the thermostat housing area and the middle/bottom of the block itself are very hot.

I'm thinking it's my thermostat jammed shut after sitting still for 3 years or my water pump not getting enough coolant around. I'll change both and report back.

I'm also looking into how to install a more reliable aftermarket temp gauge

Edited October 6, 2010 by jackbyo

[jackbyo]

Ok so maybe I can just ask a few more questions...

 

I went to a place called Airco nearby that deals entirely with gauges and the like.

The dude hooked up a device (multimeter?) to the female wire that normally hooks onto the sender, and then turned on my car and watched my cars temp gauge as he checked it against his device. He then said the sender needed to be a resistance pretty much exactly as what's listed above (332 cold, 23 hot) and got me the right sender to suit. (turned out to need a 16x1.5 thread after all... :bash:)

 

my main question is that by doing that, has he checked the integrity of the wiring and gauge?

next question is, what did he do to check it? Did he use a multimeter? I'd like to be able to do this stuff myself, so I just bought a multimeter from jaycar

 

and finally what I'd like to do to be sure is put an aftermarket (maybe digital) gauge somewhere discreet just for peace of mind. I was thinking I could get a gauge that matches a sender that'll fit into the block drain tap at the front of the motor. is there anything wrong with that plan?

Edited October 6, 2010 by jackbyo

[ke70dave]

yeah he used a multimeter to test your sender unit.

 

the unit produces a resistance bewteen the tap on the unit (where the wires goes) and ground.

 

and since it screws into your engine block the ground is through the body of the sender unit.

 

so he got you a new sender unit? did it fix your guage?

 

his test only tested the resistance of the sender itself, it did not check the wiring or the guage itself.

 

getting an aftermarket guage/sender is a really good idea, have a look into the VDO guages, you pay a bit more but they are very good quality, available from repco for about ~$80 or so. and they have the old school look to them, so fit in with old cars guages. i have one of these, they arent digital, just analogue, but look good and most importantly work good!

 

your chosen location seems fine to me.

[Evan G]

NTC (negative temperature coefficient) resistance lowers when the temp rises

[altezzaclub]

What's the story with the thermostat jacky? Checked it yet?? or did the sender unit fix the problem.

[jackbyo]

sorry I shoulda been more clear

 

I picked up a thermostat and thermostat gasket today but supercheap is ordering in the water pump for me. I'll put that in in the morning.

 

But yeah the sender 'fixed' the temp gauge being dead, but it went to hot in just a few minutes of driving!

even after I flushed the radiator and put new coolant in, it's still going right to hot... thing is that the radiator cap isn't even warm, but if I feel around the thermostat housing and where the sender is it's like burning hot.

SO that's making me think that the thermostat is the culprit because it's probably not letting any coolant get through. Remember that I got this car off a girl who left it sitting in a garage for 3-4 years.

 

SO job for tomorrow is my first thermostat replacement. Also, I did flush the radiator by disconnecting the bottom hose and running clean water through the cap until it went clear, but I think if the thermostat really has sealed shut then I probably need to flush out the coolant jackets in the block itself. I can just blast a hose through the thermostat hole and let it flush out through the coolant drain tap on the block right?

Edited October 6, 2010 by jackbyo

[altezzaclub]

You're better to hose the block out when you take the water pump off I think.

 

The bigger the hole and the more flow you can get the better, but it still won't move the rust. I used a srewdriver and wire on the block when I had it out.

 

It certainly sounds like the thermostat has jammed shut.