Overheating

[FI Spyder]

On FI cars it's much easier, fill is by the expansion tank. Thermostat is horizontal so you can position the jiggle vale at the top for air to escape.

Beans suggestion is sound about leaving time for air to escape (I never rush any procedure). All that being said, when the system is full I start the car and vary rev's and watch the air being pumped into the expansion tank refilling as necessary. Eventually the water level will rise as the coolant expands necessitating a quick installation of the rad cap. When it cools and water is sucked back into the engine add more coolant to the tank. Check level after a few drives, adding coolant as necessary until it stabilizes as all the air is expelled from the system in the course of driving.

With carbs and vertical thermostat it will be a little more difficult for air to get pushed out the jiggle valve but principal should be the same with possibly a little help by squeezing upper or lower hoses.

For people with dehumidifiers, the water you get in the bucket is distilled and makes for good mix.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[g4zur]

Good afternoon all
No update yet. Raining all day so unable to get stuck in.
Mildrid I did buy a digital thermometer as you suggested. The old thermostat was jammed fully open. Tried yet another new stat in saucepan on cooker heated up and opened up at 87 deg C so should be ok. Hopefully able to attack tomorrow, Rain permitting.
Regards
Gareth


G.P.Albrighton

[FI Spyder]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by g4zur</i>

The old thermostat was jammed fully open.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

They don't get "jammed" open per se. It is under spring pressure so when they fail the spring will keep them open so the car doesn't over heat. On a cold gay however you'll not much heat out of the heater as I found out when mine failed on the Integra in winter (yeah, I know, we don't really get winter here) and the temp gauge would barely move and only cool air came from the heater.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[g4zur]

Good afternoon all.
Update on problem, Spent the morning working on car, As I previously stated, Checked the new stat in saucepan on cooker and opened at 87 Deg C.
Fitted new stat but as Hasbeen suggested filled top hose till overflowing new gasket. topped up header tank ran engine till got hot squeezing hoses to release air with pressure cap off. temp. gauge went up to 3/4 again but I was checking with the thermometer, Stat opened at 87 deg circulating water. then went for a drive and all seems well. Then I remembered before I started the work It always showed about 3/4. Seems high on gauge but when I got this car 6 months ago the heater gauge didn't work at all till I fitted a new sender unit. Rad is now getting warm as all the hoses and heater working. As I said The gauge just above 3/4 when thermostat opens and stays there. Food for thought.
Comments/opinions most welcome.
Many thanks.
Regards
Gareth.

G.P.Albrighton

[FI Spyder]

Use your infrared gun to check temps on upper and lower rad hoses, different spots on the rad (it's cross flow) to get an idea of operation temps. Not sure what they should be (some one else may have temps recorded) but if you have access to another TR7 with gauge reading in lower third you can compare temps to the different spots. While all connections in the gauge circuit should be clean so as not to introduce resistance, it may be just the gauge giving that particular reading for the current going through the circuit.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[Workshop Help]

I beg your pardon once again. In your initial post the thermostat rating is shown to be 88 degrees Celsius. By my primitive calculations involving all my fingers and toes, and some chalk with my slate, your Celsius converts to my Fahrenheit of 190.4 degrees.

Whoa! That's getting up there on the hot side. The use of the 180 degree F. thermostat gives a temperature gauge reading of between 3/8 and 1/2 the way on the gauge. Your thermostat is what the U.S. E.P.A. wanted for emissions standards back in 1975 and was a contributor to the popping of the plastic/nylon filler plugs on top of the thermostat housings with the resultant head warpage disasters.

Your gauge reading to the hot side would be normal for that hot of a thermostat. But, if you happen to live and drive in the exotic locales north of the arctic circle, this would be a wise choice as you want the heater to work stronger than with a cooler rated one.

Were you aware of this? Modern cars use these hot thermostats but have much stouter internal cooling passages and head castings than Triumph had back 40 years ago. Try a 180 degree thermostat and see what happens. The temperature gauge should read just below the half way mark and the heater will still work just fine. It's kept me cozy for all these years.

Mildred Hargis

[Beans]

Later models TR7 hazve 88°C thermostats fitted.
With everything in good condition reading should be between the ¼ and ½ marks on th etemperature gauge.
But you mentioned you fitted a new sender, might be the cause for your gauge overreading

<center>
<font color="blue"><i>1976 TR7 FHC (needs some TLC ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng
</font id="blue"><b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="3"><font color="red">My full Weblog</font id="red"></font id="size3"></b></u>[/url]</b></i></center>

[Hasbeen]

Gareth what temperature are you getting at the thermostat housing, on the top hose, & at the top center & bottom of your radiator, with your new infrared temperature gauge.

Take readings when your in car instrument is where it usually runs, & let us know.

Hasbeen

[g4zur]

Good evening all.
Many apologies for the late update, My wife and myself have both had terrible colds, This morning I took out the heater gauge sender unit (fitted about 4 months ago) checked the resistance it showed 680 Ohms. Checked a spare new one which showed 1030 Ohms just over 1K.
Fitted the new sender and reading between 1/4 and 1/2 after a good run. this makes sense to me. HOWEVER I HAVE LEFT THE THERMOSTAT OUT until new lower temp (75 deg C) one arrives.
Comments much appreciated.
Many thanks as always.
Regards
Gareth.

G.P.Albrighton

[FI Spyder]

Leaving the thermostat out ensures that only half the coolant goes to rad. The other half gets directed back into engine. It's the triumph "foot" that blocks off the bypass when the thermostat is open. With it being really cold you may only need half the cooling capacity like when the rad is partially blocked. See foot on picture below.





- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[g4zur]

Hi Spyder
Thanks for reply, Yes I am aware from previous postings of the "Triumph Foot" The stats I have a new one on its way have the foot, also the jiggle pin to get rid of air, What I didn't realise what the foot did, I do now, Many thanks.[;)]
Regards
Gareth

G.P.Albrighton

[g4zur]

Hi All
Running without a stat in all day yesterday and a fair few miles. The temp. gauge only went just past 1/4.
New thermostat arrived today and fitted went through correct procedure to get rid of air. The new stat is a 75 Deg. version.
Again did a good few miles, Temp gauge went barely above 1/2 then stat opened and temp. dropped, watching carefully as driving gauge dropped to between 1/4 and 1/2. and stayed below 1/2 for the whole time. After all that has happened I feel all along It was the gauge sender unit. Only 4 months old. Lesson learned. Just because its fairly new doesn't mean its ok. Many many thanks once more to the forum for all the great help.
Regards
Gareth.

G.P.Albrighton