Got the old girl hot.....quick!

[Rick1970]

Changed the old radiator (very minor leak turning into a not so minor one :angry:) in my '86 RR. Fitted the radiator from a spare 95?? Disco that I have here. Also refitted a set of EL thermo's with a 92-87 deg switch (in t'stat housing where condenser fan switch was.


The throttle body heater in mine was disconnected and plugged years ago, so I ran a 5/16" bleed hose from the port behind the EFI temp sensor to the fitting on the RH side of the radiator. Also removed the thermotime switch and moved my aftermarket temp gauge sender to this spot (I previously was in the top rad hose). Thermostat is a Tridon 82deg high flow.


All was good, bleeding system was a much easier affair with the extra hose attached. Fans switched as they should. Max temp I seen in stop start traffic was 90, down to a steady 80-85 on the open road.


Within a 500m of home from the 45km drive from work, temp went to 100 :o. Stopped a let idle, it rose quite quick to 105. Stopped a let cool for 10 and she was down about 3L of water. Ran it again, temp rose to 100 quickly again. Temp of the radiator inlet showed 85 on the heat gun.....


Let cool for a bit longer and refilled with hot water, started and temp started high, then ran down to normal, cycling with the thermos!~


Dodgy/stuck thermostat maybe?

[PLR]

Changed the old radiator (very minor leak turning into a not so minor one :angry:) in my '86 RR. Fitted the radiator from a spare 95?? Disco that I have here. Also refitted a set of EL thermo's with a 92-87 deg switch (in t'stat housing where condenser fan switch was.


The throttle body heater in mine was disconnected and plugged years ago, so I ran a 5/16" bleed hose from the port behind the EFI temp sensor to the fitting on the RH side of the radiator. Also removed the thermotime switch and moved my aftermarket temp gauge sender to this spot (I previously was in the top rad hose). Thermostat is a Tridon 82deg high flow.


All was good, bleeding system was a much easier affair with the extra hose attached. Fans switched as they should. Max temp I seen in stop start traffic was 90, down to a steady 80-85 on the open road.


Within a 500m of home from the 45km drive from work, temp went to 100 :o. Stopped a let idle, it rose quite quick to 105. Stopped a let cool for 10 and she was down about 3L of water. Ran it again, temp rose to 100 quickly again. Temp of the radiator inlet showed 85 on the heat gun.....


Let cool for a bit longer and refilled with hot water, started and temp started high, then ran down to normal, cycling with the thermos!~


Dodgy/stuck thermostat maybe?


G`day ,

did you measure how much liquid you put in it after changing the radiator ?

500 meters from home i guess your on the fans at this stage as in not above 70/80kph ?

You say you added 3 litres after it cooled 10 min then let it cool longer and refilled with hot .

Do you mean you drained and refilled or topped up ?

Where do think the liquid went ?

[DoubleChevron]

Sounds like you had a huge air bubble behind the thermostat that you didn't manage to bleed out to me :( Fun right :wasntme:

I find on some cars I have to crack the top radiator hose (radiator side) to get the majority of the air out... You can hear the radiator gurgling and hissing and it fills from the bottom up when you do this.

seeya,
Shane L.

[Rick1970]

G`day ,

did you measure how much liquid you put in it after changing the radiator ?

500 meters from home i guess your on the fans at this stage as in not above 70/80kph ?

You say you added 3 litres after it cooled 10 min then let it cool longer and refilled with hot .

Do you mean you drained and refilled or topped up ?

Where do think the liquid went ?


The last 3-4k to home is a lot of downhill.....could prob roll 80% of the way with the engine off.


Didn't drain, just topped up. Couldn't find any leaks as such, looks like it all went out via the cap.


I was 99% sure I had all the air out. Front raised, cut down coke bottle in the radiator filler plug, cycled hot-cold-hot a few times.


Seems to be working fine now, no water in oil, no bubbles in coolant. Gunna throw a new thermostat in it just in case, flush and change coolant.

[Rick1970]

Thinking about it some more......my header/expansion tank is the older style ie only one (5/16") hose, connected to the top of the radiator. No larger hose connected to the lower radiator hose as per later Rangies/Discos.


Could me connecting a bleed hose from behind the thermostat to the top of the radiator upset things at all?

[Meccles]

Not sure but never had a problem by leaving main filler on radiator - at outlet side of radiator (not cap on expansion tank) open, heater on, running, and watching to see flow of coolant as thermostat opens. Then topping up until full at radiator. Fit main filler, then put some into overflow tank. Done this with almost every vehicle I've owned except the very latest with very complex systems, and it has worked every time. I have never had to resort to bleed lines etc. Maybe just lucky?

[PLR]

Thinking about it some more......my header/expansion tank is the older style ie only one (5/16") hose, connected to the top of the radiator. No larger hose connected to the lower radiator hose as per later Rangies/Discos.


Could me connecting a bleed hose from behind the thermostat to the top of the radiator upset things at all?

G`day ,

i wouldn`t think so , if the hose sits higher than the radiator top tank at any point it wouldn`t be ideal .

The only time they don`t like bleeding that i`ve found is if something`s higher or partially blocked , i`ve never had need to uphill face .

It sounds like all that happened with yours is it didn`t get quite enough liquid
when the radiator was swapped and it was letting you know .

[bee utey]

Thinking about it some more......my header/expansion tank is the older style ie only one (5/16") hose, connected to the top of the radiator. No larger hose connected to the lower radiator hose as per later Rangies/Discos.


Could me connecting a bleed hose from behind the thermostat to the top of the radiator upset things at all?
A couple of D1s with leaky heads got a modification that seemed to work well. I tapped a 5/16"" nipple into the header tank, just under the pressure cap, to connect the thermostat bleed hose to. That way bubbles of air from the engine would rise to the highest point and be expelled from the pressure cap without losing coolant. In your case the 5/16" line to the radiator would still return the coolant minus air to the top of the radiator.

[Rick1970]

Maybe it did still have a trapped air pocket somewhere, I did notice the heater was maybe a bit lacking.


Will flush system with cleaner tomorrow, change thermostat and coolant, then see how it goes I guess.

[Rick1970]

Ok.....so heater core is at least partly blocked. Water will flow through, BUT it is noticeably restricted. Reverse flushed engine with thermostat removed, fair amount of crud came out bottom rad hose.


Tested 82' high flow thermostat (pot on the stove) against a new 82' std Stant, both opened within a deg of each other, but the Stant open further and quicker.
The Stant also stayed further open longer when left to cool. High flow one barely open when water was down to 84'.


Will flush heater core best I can for now, and mite run with the new Stant thermostat as see what happens. Look at swapping out the heater core later :angry:

[Mercguy]

When you first did the flush, did you have the heater on full?

Just have to ask as it wasn't previously nmentioned.

[Rick1970]

When you first did the flush, did you have the heater on full?

Just have to ask as it wasn't previously mentioned.


They don't have a heater tap, constant flow through heater core. So heater on or off make no difference really.

[Rick1970]

OK, its still getting hot, loosing coolant through the expansion tank overflow. Heater was partly blocked. had a measured 12L of coolant added. Cap is new. Check its full, drive 50km and its all ok. Stop, cool down and drive another 50km and its pushing coolant out the expansion tank cap. Only leak i can find is via tank/cap. Floors around heater are all dry.Run it up to temp and shut off and it will hold pressure till it cools again (without loosing coolant).

Looking at parts diagrams online, it appears i have the heater hoses from the back of the manifold to the heater core the wrong way around. Would this create a stuborn airlock? Heater seem to work ok now.

Can a dodgy head gasket pressurise the system enough to loose coolant, without putting any telltale bubbles into the coolant?

Its starting to get a tad irritating :mad:

[bee utey]

Sounds like quite a few old 3.5's with tin head gaskets that I've come across. The gaskets don't tend to blow out big chunks like the composite ones, but let compression gases into the cooling system under heavy load. If you modded the header tank to avoid bubbles being trapped in the top of the radiator you might get away with it, but new head gaskets would be wiser. The heads are probably even tolerably flat, I certainly didn't have to skim the heads in the 3 old 3.5's that I put new head gaskets on.

[Rick1970]

Mite give that mod a try. Motor was rebuilt at around 325K, its now got about 610k on it, so a leaky head gasket would not really be a suprise i guess.

[Rick1970]

So, using what i had lying around........I replaced the header tank with a later copper/brass one, with the larger hose fitting that goes to the bottom radiator hose, later model bottom rad hose to suit, bleed into top off rad + original hose from top of rad to header tank. Was going to use a Disco plastic tank, but it looked like more time involved to fit than i had to spare.

Now done 600km and no coolant loss... :). Temp will get to just over 90 in stop/start traffic, but drops to 80 quickly once on the open road.

Think i mite still throw some head gaskets on it tho.....