Heat issues!

[Musselcracker]

I have been struggling to get my heat gauge back to normal temprature ever since I have replaced the head gasket and skimmed the head on my 4y!

I have:
>Replaced head gasket and all other gaskets
>Replace thermostat twice (now running orginal toyota)
>Replaced temperature sensor and connection
>Bypassed the heater valve and running water from the head back into the block
>Replaced the radiator cap

The car ideals well and at the right temperature, however I switch on my head lights and the needles does a jump to just under half way. I drove 10km yesterday in the car and it fluctuated around the half way mark never really getting too hot but also not sitting in the correct place. Came back and got out to open the garage door, got back in and switched the car on (but did not start it) and the temp gauge was sitting in the correct spot!

My plans of actions
> Recore radiator at silverton and fill with antifreeze
> I am more convinced this is an earthing issue so I will also go see an auto elec!

I just want to find out from you guys if you have had the same problem, and to maybe throw some ideas around to make sure I have not over looked anything obvious!

I need this to be fixed to drive down to Cape Town next week!

[CasKru]

Hey Chris. This sounds simular to the problem George had. It turned out to be a loose connection in the instrument cluster. Maybe take yours out and tighten all connections and also check all your earth straps and connections.

[Hoppy]

Earth connection or the voltage stabilizer transistor on the back of the cluster

[Musselcracker]

Thanks hoppy!!
Looking forward to meeting you guys down there in the cape!

I had a thought... Pull the temp sensor off when car is at operating temp and see what happens to the gauge!
If it drops its a heat thing
If it stays where it is .. it is an electric thing?>?>?

Not so?

[Musselcracker]

What does the heat gauge do when your car overheats and your shut down!

Does it stay up at that temp or drop to the normal position?

[LouisZ]

If the ignition is on it will stay warm, over time the gauge will go down as the temp get lower of the water.

[Musselcracker]

now ou see mine doesnt!

If I switch mine off after driving, where the needle is halfway (ish), then switch to the ON position it sits perfectly where it should!

[LouisZ]

Does the needle stay half if you switch the ignition off the gauge is faulty.

[Musselcracker]

Nope... when its off the gauge has dropped down to the bottom like normal

[Toybox]

Earth connection or the voltage stabilizer transistor on the back of the cluster

Oom Allan, what would we look for on the voltage stabilizer?

[KOBUSL]

Chris, we had the same type of problem. I just couln't trust the heat gauge on my 2,8 SFA, so I installed an aftermarket item, and uncoupled the original. Only after idling for about 5 minutes, the new gauge started responding, and after driving some kilo's it settleded round the 70 or so mark. The old ( ucoupled ) gauge settled on the " normal " position as soon as the engine was idling , and stays there for the duration of the trip. I think your problem is electrical, but I didn't want to risk my engine by a faulty gauge, and a R 300 remedy. m50cw

[Musselcracker]

Thanks Kobus!!

I might just get an after market gauge if only for the trip down and see how it behaves!

[Musselcracker]

bump

[CasKru]

Earth connection or the voltage stabilizer transistor on the back of the cluster

[Musselcracker]

okay here is the progress

I bought an after market temp gauge and connected it!!

It said the engine was up around the 100 degree mark then i got scared and switched off the car!!

I took out the thermostat (toyota orginal ) and check it in the kettle .. seemed to open a bit warmer than i would have thought! Suppose to open at 82 C!!

Ran the car without the thermostat, and is running well and at just under 90 according to the after market gauge!
I have attached an additional earth strap to the engine!

Without the thermo I had flow over the radiator like i have never seen the pipes did not puff up and both at about the same temp!

I plan to drill some holes into the thermostat and see if that helps

Any thoughts??

[Toybox]

100 degrees is quite normal for coolant temperature, the addition of antifreeze and the system being under pressure will prevent it from boiling.

It does depend on where you were measuring the water temp though, before or after the radiator for example.

100 degrees at idle with a fixed fan (as you have) seems high though.

[Musselcracker]

on the top hose at the temp sensor!

[Musselcracker]

Alright the progress so far!!

Drilled three two extra holes in the thermostat! This helped a bit, driving at slow speed around town everything was great!
Hit the freeway or go up a hill and the temp gauge climbs to half way!

i have fixed up some of the EFI problems and taken out the thermostat all together. I will put in two liters (is that enough?) coolant, top up with water ... and hopefully this will get me from Durban to Cape Town on Thursday!!

so any ideas please please let me know ASAP!!

thanks guys

[Traveler]

Chris, did you get pre-mixed or concentrate coolant?

If you have pre-mixed, you need to fill the whole system with the stuff. If it is concentrate, then dilute as per instructions.

Coolant does not just regulate/restrict boiling and freezing. But it also stops corrosion in the system and it also lubes the waterpump.

Sorry for the very stupid question, did you line up all the holes in the gasket with the channels in the block?

[The Legend]

Hey Chris. This sounds simular to the problem George had. It turned out to be a loose connection in the instrument cluster. Maybe take yours out and tighten all connections and also check all your earth straps and connections.

Chris did you remove the instrument cluster and check it for loose connection?Is your vico fan working 100%

[Mud Dog]

Your problem may have the electricals playing some part, but it sounds like there is a real cooling issue. What is the condition of the radiator? Examine it closely, if the core fins are starting to disintegrate anywhere it's a problem for sure. Rather than re-core the original, just replace with a new aluminium unit .... at about R850 it's a cheaper option than new copper or re-coring.

After the head skim, the motor is probably running slightly hotter than before with the slightly higher compression ratio. It could well be that the old radiator may have just been able to manage before, but now cannot cope fully with the increased heat.

[The Legend]

I paid R885.65 for alu radiator at Silverton Radiators PART NR 376773704

[Musselcracker]

Thanks guys... i was using the coolant you must mix!!
Yes I lined up the head gasket holes ..... I am sure i did! the gasket only fits one way and on those "bails" i think!!

I didn't realise the radiator was so cheap! I think I will replace it just to be sure!

I still have a fixed fan!!

[Mud Dog]

To replace the radiator is an easy job .... half hour tops. A fixed fan is no problem .... actually better in some respects. I'd leave it unles you're planning on doing a lot of water crossings.

[Musselcracker]

Yeah I like s always runningthe fixed fan!!

At least you know it

[Musselcracker]

At least you know it is always running!

Sorry!