Why Did The Triumph Stag OVERHEAT? Classic Car Myth Busted!

[@catafalque3634]

I owned a Stag for years, never any overheating problems if you maintain it by the book. Superb car in many ways, lovely to drive, amazing sound.

[@ClassicsWorldUK]

Couldn't agree more!

[@neilhampson2843]

I owned a Stag for four years in the early 90s. I never ran it with a thermostat fitted, No problems. Also a 12 vane water pump helped. Great car with a fantastic sound track.

[@goffthomas2554]

An engine must never be run without a thermostat. Unrestricted coolant flow causes localised overheating and damage and serious oil contamination. No problems you say, I seriously doubt it! I suspect you are not a qualified MVT! Basic maintenance is key in preventing any overheating issue’s.

[@Pops1948]

@@goffthomas2554 he/she certainly didn't drive it in Australia without a thermostat . . . then again, 20 minutes in England is a long day

[@ma-li3935]

I've had 3 Stags during my life time, 2 manuals, 1 Auto, still got one now. Never had any over heating Issues, During research back then for BL Australia the only mods that were done back in the "70s was Raised header tank and bleed system same as Dolomite sprint, TR7. worked perfectly and not expensive, raised the water head to well over the water pump, and allowed continuous purge and much more efficient. Yes we stripped many motors down to clean properly internally (swarf and casting sand) before making available over the counter as spare parts. One thing else the head studs were changed around 1977 improved with different alloys, and was recommended to be replaced as a service bulletin, it wasn't a recall though. Radiator shrouds also.

[@berwhaletheavenger]

A very good modification is to fit a belt driven Ford V6 water pump - it bolts to side of the engine like it did on the V6 Essex, sits nice and low and can shift a lot of coolant. The original pump is binned. The head gaskets aren't a problem if the engine has circulating coolant.

[@royster3345]

This mod fits the Ford pump where the alternator is fitted, you refit the alternator using an aftermarket bracket up where the US market would fit the AC pump. Also throw the standard overflow bottle and fit a plastic header tank up high. Ones from Volvo plus others fit well and some have level sensors to warn you if water is lost. You don't need to update the rad, standard one is fine if checked for sediment. Do the above and you get to ditch the standard waterpump with its bad positioning so high up that a slight drop in water and it runs the pump dry. Also the water pump has a seal which when you have corrosion on the underside of the pump vane soon wears the seal caused by lack of antifreeze with its rust inhibitor. There are a lot of stories covering the design, politics, finance etc, most true, but we are talking of a car that is 50 years old, and like any this age, the enthusiasts out there have flagged and fixed these types of issues. And for that I'm very much in their debt and able to enjoy such a great V8 sound track.

[@ClassicsWorldUK]

Good to know, great tip!

[@timothyrogstad5577]

The coolant intake to the engine was also reduced in size from the prototype to cut costs. I don't know if there's a fix for that one?

[@philtucker1224]

Leaving highly abrasive sand in the waterways and oil ways during production does not sound like a good idea!! ☹️😡

[@robertlloyd7493]

😊 very insightful

[@rodneyhull9764]

What a beauty

[@triumphstagdriver]

Water pump at the highest point in the cooling system? Seriously, how much longer will this myth persist. All you need to do is actually properly look at the pump location and you'll find it to be a good 10+cm below the highest point - that being the filler on the radiator. Have a look at any other contemporary car and you'll find they all have the water pump at a similar height... You are correct about the reason of its location and that leads to another question; Saabs and Dolomites had the same pump setup yet it is only the Stag that get the bad reputation... Those other cars didn't really have any water pump problems, so why the bad rep on the Stag? Seems to me an easy target considering all the other myths that do the rounds.

[@peterriggall8409]

I did not realise there were so many reasons for the infamous overheating issues. I thought fitting thematic fans was a fix all but it is more than that. I fit an Aussie invention called Engine Guard to my old cars. Cheap insurance. It monitors engine temp. not water temp.

[@timgriggs8592]

So what is it actually measuring? And where in the engine? Serious question 😊

[@goffthomas2554]

@@timgriggs8592some engine remanufacturers fit a temperature sensitive label that monitors metal temperature. If coolant is lost then high metal temperature is not down too mechanical failure. Simple detection method! Does that help Sir? 😊

[@timgriggs8592]

@@goffthomas2554 Yes. I wasn't aware of such a device. It's a pity Rover wasn't, either - in the 90s a lot of K-series engines would have been saved!

[@ClassicsWorldUK]

Yep, the Stag had quite an uphill battle...

[@KJs581]

I had a rad hose clamp break and lost water/cooked a car, and by the time you realise, too late. That car (mid 80's) and my Stag (I used to do long interstate trips across Australia) I fitted a cooling system pressure gauge. The one on the Stag is actually a Stewart Warner fuel pressure gauge that reads from the header tank. The car warms up, gauge shows 13 lb. Of course it varies as temp rises/falls, and changes when stopped/hot soak (as does the mech temp gauge), but you learn "what is normal". The SECOND I get a leak, (or a dud radiator cap) I know. It has been on there for 31 years. It's actually older than that, as it came off the previous car that had it.

[@jimmyquinn9639]

Beautiful car ⭐️⭐️⭐️⭐️👏👏👏👍👍👍

[@stevesalvage1089]

Yes most stags are well sorted , easy fix , fit upper expansion tank like tr7 , fill proper alloy engine coolant not tap water , in the garages I worked on them no problem at all, because they were serviced , great engines if maintained,

[@ClassicsWorldUK]

Exactly, a few modern improvements help so much!

[@MrDodgedollar]

I couldn’t understand why the cooling system was changed from radiator fill cap ( like on my sanction 1 1971) to the low level expansion tank fill cap… I know by a quick tool free check if my coolant level is full ( as it should be to not knowing without a spanner- Really dumb move to rely on a stupid low level expansion tank that tells you bugger all!) I much prefer the old 13psi system that after the bypass hose update ( 25 cars before mine was built) The cooling system is fine IF THEY ARE BUILT PROPERLY AND DEBRIS FREE)

[@rob5944]

I've never heard those reasons for overheating before. For an experienced car manufacturer to design something like that is unbelievable, I'm tempted to add the word embarrassment to the words national disgrace. So it seems that in house fighting and selfish pride led to a beautiful car and another nail in the BL coffin being hammered home? It does beg one question, did Saab suffer from similar problems and why put that header tank down there?

[@timgriggs8592]

It was all the fault of Harry Webster of Triumph, who insisted that the Stag needed its own V8 and not a version of the Rover/Buick V8. He said the Rover engine wouldn't fit (untrue, as so many owners found in the 70s and 80s...). All down to the ruinous politics of BL, and dreadful quality management of course 😢

[@ClassicsWorldUK]

The Stag V8 is actually a lovely unit...if owners take the time to maintain it, fit a few retroactive improvements and look after it...

[@rob5944]

@@timgriggs8592 then he should of been told that a Rover unit was going in there and that's that.

[@timgriggs8592]

@@rob5944 He certainly should have, yes, but there's BL management for you. Instead of saying "Why on earth would we want two V8 engines in our range??" they allowed themselves to be browbeaten by Webster. Sigh....

[@KJs581]

There wasn't really as many design problems as the myths say there are. Everyday people who have them now have little trouble with them if you do things properly. The REAL problem was that BL assembled them. It is as simple as that. You introduce a high revving, alloy head OHC engine to an assembly line that can't assemble a basic cast iron head pushrod engine................ what do people expect? Or, put another way, give a Jaguar or Aston Martin engine to BL to assemble, and give the Stag engine to AM to assemble and maintain. The Stag engine serviced/assembled by Aston Martin would go forever, the Jag/Aston engines wouldn't even run. So many stories. "Casting sand in the engine". Ok, put sand in a new Honda engine, and if that has problems "Oh, bad design???" Of course not. Leaving casting sand in an engine is stupidity and slackness, nothing to do with design. Head corrosion. I have a BL tech bulletin that tells dealers to "re-use anti freeze out of old engines, as it is in short supply". NONE of us would do that, and yet BL did????? No wonder they had problems. I bought mine in `1993. At the time I was posted to Melbourne (Australia), and home was Perth. It ran hot first weekend I had it, because the "expert" who built the engine hadn't a clue/head torques all over the place. I fixed it........................ I drove mine home every Xmas leave (4 weeks) from Melb to Perth (3500 kms one way/7,000 kms return, in summer, in temps from 35 to 48 degs C. Did that almost every year for 7 trips. Leave Friday, drive dawn til dusk, arrive mid arvo Sunday. 5 hour stints at a time, sit on 110 kmh all day, and in the middle of nowhere (lucky to see two cars all day) sat on 130 kmh for 5 hours at a time/steady 4,000 rpm. Never missed a beat. (Car was an auto then and for all the interstate trips, hence 20 mph per 1,000 rpm. After I was posted to Perth I fitted the manual/overdrive it has now, that would have been nice for the cross Aust trips). My car had done 90,000 kms when I got it, and I have added 330,000 kms to that in the last 31 years, so currently sitting at 424,000 kms. It doesn't do interstate trips anymore, but I use it all the time in summer, and in Perth, it gets hot. This summer we had months of max temp over 35 deg C, and two weeks of 40/just over 40 deg temps. The car handles that heat better than I do. No car is perfect, and the Stag isn't either. But people who know them are sick of the constant repeating of myths/mistakes that were started when the cars were new, and then just constantly repeated. But, there is an advantage. Any other classic touring convertible is usually WAY out of my price range. But my Stag was amazingly affordable. So those who have never had one/never will/never worked on one? (They are the ones who "love the myths") - Keep spreading the myths and keep them cheap for us. For that, we thank you. 🙂

[@fairmont___d]

Wow, great story! So your Stag has done another 330,000 km without a rebuild?

[@mattbod]

I’d still like one it’s a shame it was built in 70s Britain. Saab managed to make the Triumph slant 4 unburstable.

[@ClassicsWorldUK]

Thankfully many of the issues can be sorted now!

[@mumwifeteacher]

I wouldn’t be surprised if the designer went on to help build the Chernobyl nuclear power plant.

[@rob5944]

With respect to the owners and the solutions mentioned here, I'd be constantly fretting that a meltdown might occur at any moment whilst driving along.

[@MegaReddevil71]

Should have fitted the rover v8 and scrapped the triumph engine

[@Pops1948]

In Australia I worked at a Triumph specialist workshop for 25 years. The Stag engine was easily the worst Triumph engine ever built, if the car had of originally been engineered with the 3.5 Rover engine it would be worth much more today

[@ma-li3935]

I beg to differ. we were going to modify and fit sprint heads

[@Pops1948]

@ma-li3935 lots of luck with that, the operative word is 'were'.

[@ma-li3935]

@@Pops1948 It was done, but I was not with them when they completed that project. Did you know that BL also prototyped with Lucas P.I. same system as TR6 on the Stag as well.

[@Pops1948]

@ma-li3935 the engine in Australia had inefficient water pump, oil pump, timing chain, heads etc. Big mileage/heat was a no no. The Buick/Rover engine would have made the underpowered Stag a great car. Lucas's injection in Australia was Triumph's Achilles heel, a laughing stock

[@ma-li3935]

@@Pops1948 12 vane water pump was also an upgrade then, the biggest problem was if the water level got too low then the height of the pump would either cavitate or worst case not pump at all (thats why JRA at the time had a service bulletin to relocate the header tank and fit the 12 vane pump). The main cause of coolant loss was at the back section of the inlet manifold, the manifold was often not installed properly allowing the coolant to weep into the valley. and dickwits who never serviced there cars properly, as well as only using water to top up coolant system. Yes the Rover V8 is a great motor, just for your info I've seen a 350 chev motor fitted in a Stag. But I am just keeping to the Stag as it was sold to the public. Don't forget the P.I. injection was a sixties thing, the stag was designed in the mid sixties, so yo have to excuse the engineers at the time to use what was on the shelf at the time.

[@roygardiner2229]

So......poor quality control and a flawed design. "Sand from the casting process left in the engine": I simply cannot imagine a Japanese company allowing that to occur. I just can't.

[@raftonpounder6696]

Correct. But their products are boring.

[@smichaelb1980]

Yeah,give me some exciting and daring lack of quality control😅​@@raftonpounder6696

[@roygardiner2229]

Fair enough. I agree that is mostly the case.@@raftonpounder6696

[@rob5944]

I said exactly that to my wife after watching this. I had a Lexus with the 3uzfe engine, a 4.3 V8 that ran like a swiss watch. I the U.S. they regularly cover over 300,000 miles. 500,000 is not uncommon apparently.

[@rob5944]

@@raftonpounder6696 I know where you coming from, but sitting in the dealership or pulling out serious cash to rebuild or replace a cooked engine can hardly be considered exiting.