Really stupid annoying fever

4A-GE · Post by **4A-GE** » Tue Apr 01, 2014 8:24 am

My '89 has been a gremlin since I got it. It's lucky it's so fun or it would've been shunted along by now.

Anyway.

This time around it's fairly serious - It heats up way more than it should.
All I can think of is a) water pump, or b) temperature gauge getting on the piss. However, the problem doesn't seem to occur if I start it with the heater on and cruise round with it on the whole time.

Seems to behave when I go home at night but not any other time.

Radiator is brand new.
Thermostat is brand new.
Radiator cap is brand new.
Coolant and complete system unfuckulation (flush) done by the radiator guys on the 28th when the radiator went in, so that's 3 flushes and air bleeds since January.
No oil in water or emulsion in oil. No white or blue smoke, so not head gasket.
Fan comes on when it should - Air con on = both fans on. Will have air con fan wired to come on when normal fan does at some stage for safety.

marcellarius wrote:When changing the coolant do you run it without the pressure cap on until you see water flowing into the radiator (indicating tstat has opened and your pump is working)?

In normal conditions the thermofans shouldn't be running, airflow should be sufficient to cool it. Do you have poor airflow across the radiator? Check to make sure it's not clogged up with leaves or crap between the A/C condenser and radiator. Is your numberplate blocking airflow? Is the lower undertray in place?

1) The radiator guys would've done that - Said the pump was working; not sure how well. New radiator was an improvement, but the heating up issue is still there.

2) Flicking on the air con is helping less and less, but it seems to be ok if I have the air con on before it starts heating up???

Someone please help before this thing becomes sentient and contracts malaria.

WideOpenThrottle · Post by **WideOpenThrottle** » Tue Apr 01, 2014 10:39 am

Get a pressure test done to see if there are any leaks,especially by the water pump ant the Tee pipes below the thermostat housing that supply water to the air pump/IAC valve...they are notorious for corrosion.

WideOpenThrottle · Post by **WideOpenThrottle** » Tue Apr 01, 2014 10:47 am

This might help?

http://www.youtube.com/watch?v=hUzOTnsWImI

4A-GE · Post by **4A-GE** » Tue Apr 01, 2014 11:47 am

WideOpenThrottle wrote:Get a pressure test done to see if there are any leaks,especially by the water pump ant the Tee pipes below the thermostat housing that supply water to the air pump/IAC valve...they are notorious for corrosion.

Looking at the motor and the ground under where I leave it (not just at home, mind), there don't appear to be any leaks. Even my rocker cover gasket is healthy, lol. The guys who did the thermostat checked (and would've cleared) the wee pipes for crap while they were in there.

GRUVBB · Post by **GRUVBB** » Tue Apr 01, 2014 11:51 am

Maybe your transducer/sender is faulty or the actual gauge display. Can you get an actual temp reading with a suitable thermometer for comparison?

4A-GE · Post by **4A-GE** » Tue Apr 01, 2014 11:54 am

Might be worth adding that all the coolant levels are constant - Forgot to write that bit in the original post.

4A-GE · Post by **4A-GE** » Tue Apr 01, 2014 11:55 am

GRUVBB wrote:Maybe your transducer/sender is faulty or the actual gauge display. Can you get an actual temp reading with a suitable thermometer for comparison?

I've been thinking about the gauge or the temp sensor after the gauge jumped around a bit today. How can I clean it out? (The one right at the front of the motor.)
Don't know where I'd get a decent thermometer but that's probably a good idea.

Also of note: Fever only happens when the car's moving.
I can leave it idling all day and it stays at operating temp.

Growler · Post by **Growler** » Tue Apr 01, 2014 1:14 pm

There is another radiator like matrix under the dash. Bypass this and see if that makes a differnce. (Its the two pipes going into the firewall on the right hand side when standing in front of the car). Becareful taking off the hoses as the aluminium pipes are very soft.
I have a similar issue where the car would overheat periodically. It was not leaking though. I have scale coming off the inside of the waterways of the block, and over time it gets caught up in the radiator and heater matrix and restricts the flow.

4A-GE · Post by **4A-GE** » Tue Apr 01, 2014 1:36 pm

Heater matrix! Right. How do I bypass it? Just bend the hose around?
Then if that is the issue, how do I clear it out?

WideOpenThrottle · Post by **WideOpenThrottle** » Tue Apr 01, 2014 1:56 pm

So if its not actually overheating then I guess it will be the gauge temp sensor at the rear of the head that's intermittently faulty?

In the pics it is above the thermostat housing & below the CAS .

GRUVBB · Post by **GRUVBB** » Tue Apr 01, 2014 3:37 pm

Sometimes the sender units can be reverse acting. It may be stable at low temp but as it warms up it may be breaking down. Check that the terminal onto the sender unit is tight..... Im not familiar with this circuit as have not had to work on mine. The auto sparky guy (name escapes at present) may be able to enlighten further..... I have thermometers with wire probes which are accurate if you need to use one.
Check price of a new sender unit. It might be cheap and then its another variable ruled out.
To clean the heater box I just disconnected both hoses and pushed the hose in and kept flushing till it flowed clear. Do from both directions as the heat control valve will probably not be modulating and may be in closed position.
You can bypass itand run motor to try and eliminate area of concern.

Growler · Post by **Growler** » Tue Apr 01, 2014 3:47 pm

4A-GE wrote:Heater matrix! Right. How do I bypass it? Just bend the hose around?
Then if that is the issue, how do I clear it out?

You can take the hoses off that go into the firewall and join them together using an appropriate piece of copper tubing and hose clips.
I bought a piece of high temp rubber hose and connected one end to the fitting at the back of the block, and the other to the side. It is my intention to buy another heater matrix and change it over at some point…but because you virtually have to pull the whole dash out to get to it, it hasn’t been high on the priority list.
I’m not too sure how to clean them…if you can at all.

4A-GE · Post by **4A-GE** » Tue Apr 01, 2014 4:20 pm

Ok, sounding good. I'm going to hose out the heater thingy when I next get a chance. Bypassing it might be more difficult than I'd like (in terms of time constraints) but it's gotta be done to find out, I reckon.

Sender unit worth investigating too. Guna pull the sensor off and see if it's clogged or whatever, try clean it up and see if the gauge behaves.

Everything's worth a try; I'm just not rich in time at the moment. Silly education.

WideOpenThrottle · Post by **WideOpenThrottle** » Tue Apr 01, 2014 5:27 pm

But wait! there's more!

If the engine runs hot,use your hand to check the temp of the lower radiator hose.If the hose is not hot, but the engine is,the thermostat is probably stuck in the closed position,preventing the coolant from the engine from travelling thru the radiator.

If the lower radiator hose is hot then coolant is flowing and the thermostat is open meaning the problem lies elsewhere.

I know you have a new thermostat but any process of elimination always helps!

Growler · Post by **Growler** » Tue Apr 01, 2014 9:19 pm

4A-GE wrote:Ok, sounding good. I'm going to hose out the heater thingy when I next get a chance. Bypassing it might be more difficult than I'd like (in terms of time constraints) but it's gotta be done to find out, I reckon.

Sender unit worth investigating too. Guna pull the sensor off and see if it's clogged or whatever, try clean it up and see if the gauge behaves.

Everything's worth a try; I'm just not rich in time at the moment. Silly education.

I tried all of that, Reverse flushing, flushing additives etc. Nothing worked.
It runs fine how I have set it up, but I don't have a heater. As I only take it out periodically its not an issue for me.
My issue is slightly different where I have put a later model engine into mine. The engine I have was a low mileage 1600 that had been sitting under a bench for 12 months (I changed engines because I had the keyway on the crank nose flog out). I'm having scale and corrosion coming off the waterways in the block which eventually clog the flow in the radiator over time. I have stripped and cleaned the radiator 3 times now and the sludge gets less and less. I have tried engine flushes etc but the only real way to fix my issue is to strip the engine completely and acid clean the block....which is on my list for one day...

4A-GE · Post by **4A-GE** » Wed Apr 02, 2014 6:48 am

Oh dude don't tell me that...

Drove it home last night; 33km trip. Heater on full heat, fan on two.
It behaved.

Diagnosis: My car hates albany.

2low2c · Post by **2low2c** » Wed Apr 02, 2014 7:22 am

My best guess would be that the blades on the water pump have rusted away and it is not circulating enough water under load.

4A-GE · Post by **4A-GE** » Wed Apr 02, 2014 8:03 am

2low2c wrote:My best guess would be that the blades on the water pump have rusted away and it is not circulating enough water under load.

Yeah - That's what I was thinking. I thought the poor impeller's probably haddit. However.

Yesterday morning after getting to school (Albany) I pulled out the little grey plug by the thermostat, blew as hard as I could into both sockets, stuck it back in, and carried on to class.

This morning, it behaved completely.

Maybe it was just a shitty connection making the gauge go nuts?

Will keep everyone posted.

WideOpenThrottle · Post by **WideOpenThrottle** » Wed Apr 02, 2014 8:10 am

That's the the sensor for the fans...maybe they werent switching on

4A-GE · Post by **4A-GE** » Wed Apr 02, 2014 8:14 am

Oh, no shit? I'll take a pic later to confirm. Fuck me, man, that'd explain enough for me to trust it again!

Pic related: My reaction when_

WideOpenThrottle · Post by **WideOpenThrottle** » Wed Apr 02, 2014 8:24 am

At idle if the fans don't come on your car will overheat if it sits for a while. So if you are in stop-start traffic and you are stationary for long enough then it will heat up.....once speed increases and with air flow past the radiator then it will cool down again.I take it your car is fine at motorway speeds?

4A-GE · Post by **4A-GE** » Wed Apr 02, 2014 8:37 am

No, that's the weird thing. It's fine at idle; the fan comes on when it should. Air con on = both fans on.

Motorway speeds, for instance, going over the harbour bridge (problem area #1 of about 4), it gets warm on the way up and doesn't cool down until esmonde road or so; that's with the air con blasting to keep the thing in check.

Today, going over the bridge was a slow crawl ~60km/h if I was lucky. The thing performed flawlessly, which is why I'm baffled.

WideOpenThrottle · Post by **WideOpenThrottle** » Wed Apr 02, 2014 9:58 am

Well, if it was me, I would be replacing the rear head temp gauge sender unit for now and hoping that's all it is!

If you take off the CAS and coil pack then it makes access so much easier.

Also I assume your motor was flushed without the radiator and thermostat?

marcellarius · Post by **marcellarius** » Wed Apr 02, 2014 10:36 am

Definitely figure out a way to rule out a bad gauge or wiring ... an intermittent short to ground on the gauge wiring would make the needle read hot, even if the sensor was fine.

GRUVBB · Post by **GRUVBB** » Wed Apr 02, 2014 11:00 am

Keep in mind that when you are running your ac that the condensor(coil in front of radiator) is rejecting heat to make the vapours condense to a liquid so this will be introducing heat around that area. It is the evaperator coil which produces cooling when evaporating it back to a vapour.

It may be just the fact that the condensor fan is increasing airflow over both condensor and radiator coils...... Could reinforce 2low2c thought that pump flow is the issue.

Really stupid annoying fever

Really stupid annoying fever

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