TR7 Toledo: Saab radiator & Volvo 850 expansion tank fitted

[Bitsa]

I've not updated in a while, but I've been busy. I wanted to fit a relay to bypass the coil ballast during starting and ended up rewiring most of the engine. I fitted some proper headlights, one is cloudy and the other has bodged bulb fitment, but I've now got a pile from my dad to make a good set from. The gauge setup in the previous pic has been binned, and I've made a 5 light display (dip/main/spot/oil/alt/OD). It's a test piece, the final is more likely to be black than orange, but I'm not hating the orange to be honest!

Speedo sensor for the Koso gauge is fitted to the drivers side from wheel, not perfect but I wanted to see if works there before I spend ages fabbing up a better one. Its accurate to about 1mph against gps after calibrating it, but sometimes under reads over 40 - I think a more accurate fitment (i.e. not a metal cable tie and tape) would fix that.



Timing is set, and carbs tuned. I'm struggling to get it to idle below 1000rpm, and I think the carbs need a rebuild. But it's running well enough for now.

It's always run a bit hot, and with the Koso gauge and matched sensor I can now get accurate temps. ooling system has been flushed with cleaner (Prestone stuff) once, then again with just water about 4 or 5 times. A decent amount of muck came out, seemed to be a lot cleaner by the end - much less crap coming out. I've fitted a 74 degree thermostat, and a 74 deg fan switch thermostat. So, I think I theory it should run too cool. It's running at about 85-90 degrees in normal driving, peaking at 95 in some situations - I wasn't in stationary traffic long enough to get past that. And this was on a sub 20 degree day, and running the heater on full blast when it was above 90. The heater runs pretty warm, not exactly a furnace though - it certainly makes a noticeable difference in

I think these temps are OK in terms of not warping the head, but still a bit high considering with 74deg thermostats it should run cold. It ran about the same with no thermostat, possibly a little hotter. The thermostat has a foot which blocks the radiator bypass, so it should run better with one fitted.

I'm going to give it another flush or two with household central heating cleaner, I've been told it works well. I'll then give it another few flushes with water before filling with antifreeze and distilled water. For flushing this time I'm going to disconnect the heater and flush that separately, and also jack up the back of the car - lying in bed this morning it occurred to me that the engine sits lower at the back, so it might not be flushing the back properly.

If that doesn't work I think the possible culprits are, roughly in order of likelihood:

Dying waterpump
Fan not powerful enough
Block blocked past the point of cleaner
Radiator / radiator airflow issues (I think it is currently a Fiesta Diesel one)

If anybody can think of anything else let me know.

I had it out yesterday for about 25 miles, and about 50 today, driving nicely after being laid up. Plenty of power, but I still think a play with timing and carbs (probably a rebuild) would make it run a bit better. Drove up to the Lomond car park by Falkland today, 200m climb in 2km, 85deg at the bottom, 95 at the top, but I wasn't being gentle. It's really nice being able to drive it again - had only went out for a quick run, but then I realised I needed fuel and and an overpriced sugary coffee. The A92 at rush hour plus tractors was grim though.

[xvivalve]

There is a drain plug on the block under the exhaust manifold; removing the bolt and flushing through that can remove a lot of extra crud that's often overlooked.

Have you checked if the brakes are binding at all; that can cause the engine to run hot too...

[Bitsa]

Perfect, I’ll pop that off and that should help. Thanks!

Brakes aren’t binding - I’m able to push it in and out of the garage without issue. One thing it just occurred to me to check is the polarity of the fan wiring - it might be pushing instead of pulling!

[cliftyhanger]

Do you know what rad you have in the car?
When I convered mine, I tried a polo rad (used on kitcars etc with 150+bhp) and the faster I drove the hotter it got, meaning I needed a bigger rad. A passat one did the trick.

A bit worried that you have set the fan at the same temp as the thermostat. That really should not be neccessary or even wise. If the cooling is adequate and 82 or even 88 degree thermostat fitted along with a fan coming on about 5 degrees higher should work.

I know you said that the sensor is calibrated, but I would be inclined to double check. Can you pop the sensor in pan of boiling water? That should be enough of a check.

[Bitsa]

I think I have a Fiesta mk3 diesel radiator, which I think is a common one to use? I didn’t fit it. It’s new and a decent size so I doubt that is the issue but I’m not ruling anything out.

I agree about the thermostats - my thinking was to get it to run too cool as a baseline then bring it up to the correct temperature, knowing I have some spare cooling capacity.

The Koso thermostat matches up with a laser thermometer so I think it’s correct, I had intended to check it with a kettle but was too keen to wire the Koso up before I did that - I’ll need to find my camping stove or take it home and run an extension down from the flat. I’ll do that before I do anything too expensive!

[Bitsa]

I’m thinking of adding a bleed point to the top heater hose - I don’t think I have any air locks but I’d like a test point to check. Would adding it there be of any use or would it be a potential point of failure for something I’d don’t need?

I think this would fit:
https://www.ebay.co.uk/itm/295112949874

[Carledo]

Most cars that have a bleed screw in the cooling system, tend to have it in the heater hoses in order to avoid air locks in the heater. So if I was fitting one, i'd go for the upper heater hose just before it passes through the bulkhead.

But in many years of modifying cars and fitting unlikely motors with complex cooling systems in my Dolomites, I have not, so far, found a bleedscrew needful.

Looking more closely at your problem, i'd consider definitely finding and removing the block drain plug to aid with cleaning and de-silting the cooling system. Definitely make sure the fan is turning the right way! Whilst the Fiesta diesel rad is a common choice for the Dolomite, and not to be rejected out of hand, check for cold spots in the rad when the engine is hot, the rad, even though newish, could be silted up beyond the ability of solvents to flush out. Especially since I happen to KNOW this car has been sat around for MANY years! Finally, replacing the rad with a modern alternative (I prefer the Saab turbo 9-3 '98-'03 one myself) normally requires the use of a higher mounted header tank, if you are still using the tiny original Triumph one low down on the flitch, this won't help!

Steve

[Bitsa]

Good that the bleed screw is not necessary. I'd already bought it before I asked, so it'll get added to the pile of misc "this might be handy one day" bits.

The radiator was fitted about a year, year and half ago just before I bought it, with less than 1500 miles since then. I think the system was flushed at that point, so if it was flushed with the new rad fitted it could have filled with crud waiting in the engine, or stuff that has floated in there since then. I'll check for hot spots and won't rule it out. I've got the old alloy rad that needs recored in the attic, and I'm not adverse to a upgrade to something modern that can be persuaded to fit.

I'll get it flushed with the block drain plug out ASAP. I think my bottle of chemicals is coming Monday, might flush it with water see what comes out tomorrow if I have time. I figure the chemical stuff will do more good if I get any loose stuff out first.

Header tank is aftermarket. Could be a bit higher - I've looked at the Volvo options and that's quite tempting. I might just see if I can raise this one a bit, but it's a pain trying to check the level with this one. Oh and I will rotate the sensor in the pipe so it picks up temp properly if the pipe isn't full - it works fine though.


Click for big.

Thanks Everyone!

[xvivalve]

Sometimes when you remove the drain plug you need to tease a plug of jelly like substance from within with a bit of wire before coolant will flow out!

[Bitsa]

Got the plug out, no delicious jelly however. Flushed it with water, got plenty of muck out - I took the top heater hose off and flushed from either side of that too.

It’s still running hot, possibly a bit better though. I’ll do some chemical flushes with a good clean with water in between and see how it goes - I think the theory of the radiator being blocked is looking more likely.

Going to head over to the in-laws to use their hosepipe, as I don’t have water at the garage I’ve had to carry all the water for flushing down three flights of stairs, then put in in the car and drive it over the Tay Bridge! While I’m there I can borrow an extension cable and kettle to check the temp sensor. I was still getting muck out when I ran out of water, and that was with a 25l Jerry Can!

[Bitsa]

Flushed it with a hosepipe, much better than my poxy battery powered power washer, found it was struggling to take all the water when I piped it in via the engine side of lower heater hose connection, then it suddenly starting flowing better - not sure if doing that knocked a blockage loose. I’ll do another chemical flush - if I did clear a blockage I imagine there will still be some muck that the flush may shift.

I also discovered I had wired the fan backwards. I’d checked it a few times, forgetting that pushed and pulled air feels similar if you just check by hand. A bit if paper quickly confirmed it was definitely wired the wrong way

Both of these have helped but I still don’t think it’s quite right. Going to pull the radiator out and flush it upside down etc. Bit of a Hail Mary so I’m looking at new radiators. Another Fiesta derv one, Saab, and Passat (do you remember what model you used cliftyhanger?) are all on the cards. I’ve seen a few others that might fit - Nissens listings on eBay handily have diagrams but I need to get out to the car with a tape measure.

[Carledo]

The fan will make a BIG difference!

Instead of helping airflow it will stall it, right where the rad is! Ask me how I know! And give you all the best symptoms of a blocked rad! Especially since you have it cutting in so early. Personally I wouldn't want the fan to come in till AT LEAST 90 degrees even in my most conservative Sprint builds. My Vauxhall powered cars have the fan in at 98 and out at 95 with a 92 degree stat! This high but narrow range, means the fan is on and off like a yo-yo when sat in traffic for more than 3 or 4 minutes, but, once on the move, it NEVER comes in, except the one time I lost a ruck of water and didn't know it!

Steve

[ClassicFan]

The fan will make a BIG difference!

Instead of helping airflow it will stall it, right where the rad is! Ask me how I know!

Electric fans by the way they are mounted restrict air flow.

Back in the 60's/70's before (most) cars had them, people (my father included) used to take the fan blades off mechanical systems to improve fuel economy. If you go back further cars often only had 2 blade fans and simply relied on air flow through the radiator to cool an engine plus didn't have 'pressurised' cooling systems.

My old 1911cc Citroen Traction Avant didn't have a pressurised system and ran OK 99% of the time, even on the French autoroutes, it was only after running at speed then having to 'queue' in trafic did the temperature go above 100> Personally Bitsa, if your still concerned, get a modern radiator with the 'cores' in line to maximise airflow.

[Bitsa]

Yeah, it definitely made a difference. When stopped it still helped a little, even running backwards but would have been working against me at speed.

I’ve got a 95 degree switch for the fan, which I might fit if I keep it in the top hose, or I might fit 90 or 92. 95 is perhaps a little high for comfort with the TR7 block (I didn’t find much info on what a “safe” hot temp is for this engine) but I have the fan on a switch too, so I can preempt the sensor when I expect to need it, and use the sensor as a safeguard.

Alternatively I might keep the 74 degree sensor and fit in the bottom hose - some cursory research suggests this would have the same effect as a 90ish top sensor.

I only did a short drive after the last flush and fan rewiring, but it sat between 85 and 88 for the drive, hitting 91 when I pulled up the garage (it’s at the top of a steep 20mph hill) and it was passing 95 by the time I got the garage open and car in. Given this is with 74 degree thermostats, it still seems to be struggling to keep cool. I’m not expecting it to sit at 74, but if I can keep it stable in the 80s I’ll be happy and fit the higher temp stats.

I bought a Volvo 850 expansion tank, the current one has very little headroom between what I think is min and max, and being solid is very hard to see the level in the first place!

[Bitsa]

In a hope to end the messing about trying to get it to run cool, I decided to bite the bullet and just buy a new radiator. I went for the Saab 9-3 YS3D 98-03 rad, which is known to fit with minimal modification. I got the auto one with the built in oil cooler, which I wouldn't necessarily recommend (I'll get to that later). In fact, by the time I bought all the bits to fit in I was getting close to how much it would cost for a decent dolly sprint radiator - I reckon about £200 vs £250+?

I looked at a few other options, which may have worked, but seeing as the Saab one is a known quantity I went with that. 



Fiesta rad VS Saab rad

Other possible options:

Citroen C4 VTR 2.0 Litre Petrol October 2006 to October 2007 - Sized nicely for fitment, but lower hose is on the wrong side. Would rather not have a carbuncle of connectors to make an S pipe.  https://www.ebay.co.uk/itm/314709740302

Landrover 2.5 TD - Once again nice size, very deep but possibly too deep to have clearance once the fan was fitted. Also expensive. https://www.ebay.co.uk/itm/314592925268

Ford Cougar / Mondeo 2.5 Petrol - Big bugger, cheap, but would have to be fitted quite far back due to size. Therefore I’d need to use a pusher fan in front, which would be less effective. https://www.ebay.co.uk/itm/234943244552

I also looked at 80’s Sierra / Granada radiators, Volvo 240 / 750, etc. In the end I decided to avoid the risk of getting something that might not fit and bought the commonly used Saab 9-3 one - the auto one with the oil cooler, which I’m planning on using later. I’m aware of the risk of oil/coolant mixing if it fails - but it’s a brand new rad, and if it fails that’s bad news integrated oil cooler or not.

I'll split this into a few posts due to the character limit.