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Help! 308 running hot

Started by _76S.L.R_ , Jan 02 2013 05:32 PM

New alloy radiator

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#176 _76S.L.R_

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Posted 07 January 2013 - 07:06 PM

Tested again and something still not right, the fans whirled away for nearly 10 mins and it could only bring the temp down from 100 to 90( on my temp gauge) it will not go lower and let the fans turn off,they just keep on going and this is the same problem it had with the old radiator that was definately stuffed!.

Thermostat housing temp taken just after thermostat opening 83 c ( tehermostat is an 82c,all good)

Top Hose after thermostat open and fans going 65 c, bottom hose 55 c

Top Radiator Tank after thermostat open 77 c ,bottom tank 63 c

After fans had been going for about 5 mins

Thermostat Housing 74 c

Top radiator tank 63 c, Bottom Radiator Tank 50 c

Fans are kicking on when my gauge says 100 c , if I test the coolant with my Thermometer it shows a reading of around 15 degrees cooler than my guage says. As I said the Fans just keep going once they start up!?

Edited by 76S.L.R, 07 January 2013 - 07:11 PM.

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#177 hanra

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Posted 07 January 2013 - 07:31 PM

Id probably be focusing on the thematic switch then. It's temp/ and location. What type or brand is it? How exactly is it mounted.

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#178 _76S.L.R_

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Posted 07 January 2013 - 07:42 PM

As ive said before: its an 80/ 85 temp switch located in the top tank ,I'll have to get my pics hosted on photobucket and pasted here tonight to clarify it all ......I cant see a brand on it but it says made in Italy on it. Its a single pin sensor

Edited by 76S.L.R, 07 January 2013 - 07:43 PM.

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#179 ls2lxhatch

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Posted 07 January 2013 - 07:53 PM

When you take a reading with the IR temp gun make sure you have it close to the object you are measuring. The IR temp gun is basically a camera that will tell you the average temperature of the area it is looking at. The further away the gun is the larger the area measured. Often there will be a guide stamped on the gun that shows the size of the area measured at different distances. The laser pointer just lets you know where the centre of the IR sensor is aimed.

It may be that the fan temp switch range is not a good match for the thermostat and the cutoff temperature is below the water temperature when the engine is running with the thermostat partially open. In theory the water coming out of the 82 thermostat should be 82 or higher. I would think a 85/90 temp switch would be more suitable.

I would measure the temperature at the fan temp switch when the fans turn on and the temperature when the fans turn off. Turn the engine and fans off once the fans turn on and then every couple of minutes switch the ignition on and check if the fans are still on. When the fan temp switch is off check the temperature at the fan controller probe.

Edited by ls2lxhatch, 07 January 2013 - 07:54 PM.

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#180 TerrA LX

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Posted 07 January 2013 - 07:58 PM

If the heads are cracked or the gaskets blown then there would either be oil in the coolant or coolant in the oil. Both of which should be reasonably obvious.

Ah that BIG negative, I have seen plenty of gaskets go in several directions, including water to cylinder, missing the oil and seen one Holden V8 go straight out the side of the block, missing both the water and oil jackets totally.

If you are getting cylinder gases in the coolant causing overheating you need a TK head gasket ceck to confirm.

One quick test I do is to find a plastic bottle with a large neck, cut the base off and wrap some electrical tape around the threads so when inverted into the radiator cap neck it will seal.
Fill it with water and start the engine, if you get bubbles then it is most likely a cracked head or blown gasket allowing gas into the cooling system.

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#181 _torbirdie_

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Posted 07 January 2013 - 08:21 PM

It may be that the fan temp switch range is not a good match for the thermostat and the cutoff temperature is below the water temperature when the engine is running with the thermostat partially open. In theory the water coming out of the 82 thermostat should be 82 or higher.

I agree, the temp switch is within the operating range of your thermostat, that's most likely the reason they keep running. Either put your present switch in the bottom tank(may still be too low a value), or put a higher one in the top tank. As previously I'd suggest 95+.

the fans are switching on in the 95 deg range, which I believe is fine, they should only be there for the 1% of the time when the car isn't moving and it's not that imperative that its operating at its optimum temp while stationary, it's certainly not going to sustain any damage.

Also having the switch considerably above the max open stat temp prevents the annoying start up of the fans afer a heatsoak stop, reasons as to why I reckon switch is better off in bottom tank where it won't be subject to that or indeed it not activating if the coolant level drops below the sensor in the top tank.

So it would appear prob solved? , in those measurements you've posted it never got above the stat temp, if you are getting the same readings on your over reading gauge on cruise then it is all good

Edited by torbirdie, 07 January 2013 - 08:25 PM.

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#182 _76S.L.R_

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Posted 07 January 2013 - 09:21 PM

Is there any way to try calibrate an aftermarket Temp Gauge to give more accurate readings??.

With regards to fitting a higher temp thermo switch = surely the fans should still be taking the temp down in my car more than 10 degrees!, Im positive it use to take it down MUCH more than that!?

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#183 TerrA LX

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Posted 07 January 2013 - 09:39 PM

Is there any way to try calibrate an aftermarket Temp Gauge to give more accurate readings??.

Mechanical or electric?

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#184 _76S.L.R_

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Posted 07 January 2013 - 09:49 PM

Its an electric Gauge, if not possible I'll try find out what ones are concidered accurate and buy one of those instead...

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#185 _torbirdie_

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Posted 07 January 2013 - 09:50 PM

Is there any way to try calibrate an aftermarket Temp Gauge to give more accurate readings??.

With regards to fitting a higher temp thermo switch = surely the fans should still be taking the temp down in my car more than 10 degrees!, Im positive it use to take it down MUCH more than that!?

I'm not completely sure what you are asking here, but you even if you had 50 times the airflow through the rad the thermostat will still release coolant at about 75 -80C in to the top tank, it can't go lower than stat temp.

Also looking at your top and bottom difference, you have a difference of 13C, which is reasonable with possibly coolant flow restricted due to the stat probably being only half open. If the thermostat was removed the coolant would be moving faster and you'd have a lower temp difference between top and bottom,

Perhaps previously you ran a lower temp stat that was a better match with your temp switch?

Edited by torbirdie, 07 January 2013 - 09:52 PM.

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#186 TerrA LX

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Posted 07 January 2013 - 10:15 PM

Its an electric Gauge, if not possible I'll try find out what ones are concidered accurate and buy one of those instead...

You really need to figure out (with an ohm metre and thermometer ) whether it is the sender or the actual gauge at fault.

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#187 _torbirdie_

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Posted 07 January 2013 - 10:30 PM

Its an electric Gauge, if not possible I'll try find out what ones are concidered accurate and buy one of those instead...

You've got your I'r temp sensor now, just blank of the rad and stop the fans from coming on and let the temp rise and see what the ir says and note what the Gauge is saying, then it's calibrated.

You mentioned that the gauge went full scale at one point? It's a long shit, but worth checking that somehow the trigger wire for the relay isn't getting its feed of your temp sender wire. If it was also feeding a relay it would read higher.

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#188 TerrA LX

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Posted 07 January 2013 - 10:37 PM

It's a long shit, but worth checking that somehow the trigger wire for the relay isn't getting its feed of your temp sender wire.

Muuuuum DA said a bad word.

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#189 _76S.L.R_

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Posted 07 January 2013 - 10:47 PM

So whats my BEST option here =
Install a Lower temp opening Thermostat.
Install a Higher Rated Thermo Fan Sensor.
Remove the Thermost Completely?( this is what the Guys at Veale Auto Parts Suggested)

What I was getting at was = when I originally fitted the AU Fans, when they Kicked on ,the Temp use to absolutely rocket Downwards and it use to take the temperature of the coolant down in temp by double what it does now,(thats how I recall it anyways) whereas now they kick on and takes the temp down like 10 degrees and it takes some time to do so( if stopped in the driveway). As to what rating of Thermostat I had installed at the time I have no idea??.

The other day coming back from my brothers , after giving the car a bit of stick the fans were going for some time and it had not moved the temp down at all!!, my temp gauge was showing 100 and no sign of lowering?? I thought it was going to cook!....

Edited by 76S.L.R, 07 January 2013 - 10:50 PM.

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#190 TerrA LX

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Posted 07 January 2013 - 11:05 PM

Wouldn't hurt to rip the thermostat out and take it for a run, if the temp gets no where near what you got now then you need a new thermostat.
If you get similar temps I would be looking at the water pump if all else checks out.

( you have checked the flow on the new radiator, just to rule out poor production)

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#191 _76S.L.R_

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Posted 07 January 2013 - 11:13 PM

The Thermostat is brand new and I tested it correctly before fitting it ( thermostat held with Feeler gauge in hot water and temp recored with Thermometer when Thermostat dropped)

Water Pump is also brand new, cost me $70.00!! and is the correct Cast Impeller type pump= seems no matter what I do those damn fans can not keep the temp down!?

I'll test again tomorrow with no Thermostat,though numerous people have told me to leave one in?!

Edited by 76S.L.R, 07 January 2013 - 11:15 PM.

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#192 TerrA LX

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Posted 07 January 2013 - 11:23 PM

Oh yes, leave one in, you are just removing it for a test.

Sorry I didn't know everything was new but if you got air flow and all else checks out mechanically (head gasket, tune, radiator and CAP etc) then it must be a coolant flow problem.
Process of elimination.

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#193 S pack

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Posted 07 January 2013 - 11:29 PM

In an earlier post you said the thermostat you removed had 160A stamped into the wax pellet casing. Maybe you misread it and it actually reads 160F.
In any case I think the 160 stamping will mean 160 deg F, which is equal to 71 deg C and would have been a reasonable pairing with the thermo switch you have for your fans.

I have a 74 deg C thermostat in my 202 and a 95 deg C cut in temp for the thermo fan. Works well and doesn't really need to bring the temp way way down, just bring it down enough that the duty cycle of the fan isn't excessive while stuck in traffic etc. My main concern though when I installed the thermo fan was that it keep the coolant temp at or below 95 deg C.

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#194 TerrA LX

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Posted 07 January 2013 - 11:38 PM

Wouldn't hurt to pressure test the system and cap aswell.

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#195 Lima31

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Posted 07 January 2013 - 11:48 PM

Did you sort out the temp gauge reading, if you say it is reading 10 degrees too high and you're reading 90 after the fans kick in for 5min then it's actually sitting around 80, so you have no problem right ...???

Only other aspect I can think of that appears not above is whether you have the right size water pump pulley, and whether it needs to be smaller to turn the pump faster.

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#196 _76S.L.R_

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Posted 08 January 2013 - 12:39 AM

PICS AT LAST! ( photobucket been playing up!) and yes that big long thermostat bypass hose has been replaced with the proper factory hose now!

Posted Image

At some point ,looks like some time ago ,one of the water pumps has been rubbing here??!
Posted Image

Relays etc for fans

Posted Image

Edited by 76S.L.R, 08 January 2013 - 12:46 AM.

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#197 _76S.L.R_

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Posted 08 January 2013 - 12:58 AM

more pics
Altered radiator plate for fan sensor
Posted Image

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#198 _76S.L.R_

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Posted 08 January 2013 - 01:15 AM

More Pics

Old Tin Impeller pump

Posted Image

New Cast Impeller Pump ( 10mm wider Diameter)

Posted Image

Im guessing blocking up these holes will improve slightly??

Posted Image

Edited by 76S.L.R, 08 January 2013 - 01:21 AM.

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#199 _torbirdie_

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Posted 08 January 2013 - 06:02 AM

So whats my BEST option here =
Install a Lower temp opening Thermostat.
Install a Higher Rated Thermo Fan Sensor.
Remove the Thermost Completely?( this is what the Guys at Veale Auto Parts Suggested)

What I was getting at was = when I originally fitted the AU Fans, when they Kicked on ,the Temp use to absolutely rocket Downwards and it use to take the temperature of the coolant down in temp by double what it does now,(thats how I recall it anyways) whereas now they kick on and takes the temp down like 10 degrees and it takes some time to do so( if stopped in the driveway). As to what rating of Thermostat I had installed at the time I have no idea??.

The other day coming back from my brothers , after giving the car a bit of stick the fans were going for some time and it had not moved the temp down at all!!, my temp gauge was showing 100 and no sign of lowering?? I thought it was going to cook!....

It has been revealed previously that you were indeed running a 160F thermostat = 70C. That is why when the fans switched on at about 80-85 the temp dropped down 15C or so on your gauge.

Ill have another go at explaining this:

Basically there is little cooling of the water once it passes from the stat to your top tank where the sensor is located. Once the car has reached operating temp the temp in the top tank cant fall below the temp that your fan switch activates at and hence your fans stay permanently on. The fans are indeed doing something, they are cooling the water in the radiator and the water coming out the bottom would be much colder than if they were not going. However, you cant see this as your gauge(it wont show a lower reading) is measuring the temp of the water at the top of the engine, not what is coming out of the bottom of the radiator.

Yes, you have two simple alternatives to fix this prob as I see it:

put the 70C stat back in

or put higher rate temp switch in.

I would do the latter, the only good reason to be running well below optimum temp, which is ~85-90C, is if your engine is very tight in the rings.

As far as I am concerned, this is all that is happening and any further testing, (pressure testing, trying no thermostat) is a waste of time and money.

Im sorry I didnt pick up before about how your temp switch and thermostat were very similar in temp range, I was blinded by the info you provided in that your temps were well above normal, and it turns out they weren't. (a common issue when running temp problems are listed)

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#200 _The Baron_

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Posted 08 January 2013 - 10:43 AM

Im guessing blocking up these holes will improve slightly??

Yes.

Cut the corners off following the same profile as the bottom of the radiator and then blank off the exposed hole for a nice finish. Air flow will take the path of least resistance, blocking these off will help flow through the radiator.