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Triumph · Known Issues

1972 Triumph TR6 Problems: 6 Known Issues

1972 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated August 2026

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Issue summary

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1972 Triumph TR6 has 6 documented known issues, with 2 rated critical. The most serious are Crankshaft thrust-washer wear and excessive end float ($60-$3,500 repair) and Cracking differential mount (studs rip out of the frame) ($150-$900 repair). Across all issues with published estimates, repair costs range from $60 to $3,500. DIY maintenance guides at au7o.io.

In This Article

  • TR6 Engine1
  • TR6 Drivetrain1
  • TR6 Electrical1
  • TR6 Fuel System1
  • TR6 Cooling1
  • TR6 Suspension1
  • Recalls4
  • FAQ
Get Started
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In This Article

  • Engine1
  • Drivetrain1
  • Electrical1
  • Fuel System1
  • Cooling1
  • Suspension1
  • Recalls4
  • FAQ

All 6 Known Issues

Filter:
ALL YEARS19761975197419731972197119701969

On the 1969-1976 Triumph TR6, the straight-six uses semicircular (half-moon) crankshaft thrust washers at the centre main rather than full-circle thrusts, and the soft lead-indium face wears quickly. As they wear, crankshaft end float grows beyond the 0.006–0.008 in spec; past about 0.015 in the coating is gone and once the alloy wears through to steel it accelerates, scoring the crank thrust faces and eventually letting a washer drop into the sump. Riding the clutch at stoplights drives the wear hard. Worst case the crank walks fore-and-aft and destroys the block thrust faces — a full bottom-end job.

Common Symptoms

  • Measured end float over 0.008 in growing toward 0.015 in
  • Knock or fore-aft crank movement felt at the clutch
  • Metallic flakes/half-moon washer found in the sump
  • Crankshaft thrust face scoring on teardown
  • Low oil pressure / debris after break-in of a fresh rebuild

How to Fix

Check end float with a dial indicator (lever the crank fore/aft) at every opportunity and especially after break-in; if it exceeds ~0.010–0.012 in, pull the centre main cap and fit oversize thrust washers to bring float back to 0.006–0.008 in. Restorers bulletproof this during a rebuild by fitting quality thrust washers and, on the best builds, having the bearing holder machined for bronze thrust washers/bushings instead of the original whitemetal. The cheapest insurance is the driving habit the community insists on: put the gearbox in neutral and release the clutch at stoplights instead of sitting with the pedal down.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Good Parts heavy-duty bronze thrust washer for TR250/TR6, selectable thickness

    selectively restore crankshaft end-float only after measurement and thrust-face inspection Fitment/availability: Triumph TR250/TR6 2.5L six-cylinder center-main thrust position; sold individually, so final quantity and thickness must fol…

    Good Parts

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$60 - $3,500

Research This Issue

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Community Reported
High ConfidenceVerifiedReviewed Jun 2026

On the 1969-1976 Triumph TR6, the diff is hung from the frame on a forward 'mustache' bracket and rear mounts. The forward differential mounting points are prone to cracking; the right-front point fails first because it carries the most torque load. As the mount works loose the crack propagates and, if ignored, the mounting studs eventually tear out of the frame, letting the diff move under power. The classic tell is a rear-end 'clunk' on sudden throttle application that starts intermittent and progresses to every power-on/off transition.

Common Symptoms

  • Rear 'clunk' on sudden throttle on/off
  • Driveline shudder or movement when loading/unloading the drivetrain
  • Visible crack at the forward diff mount cross-member
  • Loose or pulled diff mounting studs
  • Worn/collapsed rubber diff mount bushings

How to Fix

If caught early you may only need fresh rubber diff mounting bushings, but the proven bulletproofing fix is a reinforcement kit: weld in a Moss/Sport Car Parts differential-mount repair kit that adds new studs, brackets and (on the front) reinforcing plates that spread the load and stop the crack from returning. The job is done with the diff out — grind out and weld up any existing crack, fit the reinforcing plate over the cross-member, install the new pin/studs, and renew the mount bushings at the same time. Polyurethane diff mount bushings are a common durability upgrade over the soft OEM rubber.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • British Parts Northwest 140009K front differential-mount repair and reinforcement kit

    repair and reinforce a structurally confirmed cracked or pulled front differential mounting point Fitment/availability: 1969-1976 Triumph TR6 and related TR4A/TR250 front differential-mount branch; requires welding and must be matched to…

    British Parts Northwest
  • Moss Motors 683-121 SuperPro complete differential-mount kit

    replace confirmed worn differential mounts after the frame and mounting pins are repaired or verified sound Fitment/availability: 1968-1976 TR250/TR6 front and rear differential bushings; confirm the owner accepts the polyurethane noise …

    Moss Motors

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$150 - $900

Research This Issue

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Community Reported
High ConfidenceVerifiedReviewed Jun 2026

On the 1969-1976 Triumph TR6, like most British cars of the era the TR6 runs Lucas electrics with bullet-connector harnesses, a 16/17ACR alternator and lots of in-line earths through the body and bulb holders. Decades of corrosion at terminal blocks, the positive battery cable connections, the brown feed wires and the ignition-warning-light circuit (alternator brown/yellow + ignition white) cause flickering lights, no-charge faults, and a warning lamp that lies. Owners report that even a brand-new harness won't fix a charging fault when the real problem is a corroded earth or a tired regulator/alternator.

Common Symptoms

  • Ignition/no-charge warning light glowing or flickering
  • Battery not charging despite a 'good' alternator test
  • Dim or intermittent lights and gauges
  • Voltage that drops with revs / wandering ammeter
  • Hard starting traced to corroded brown feed or earth connections

How to Fix

Restorers cure it at the root: fit a quality reproduction wiring harness, then clean and protect every earth point (engine-to-frame and frame-to-body bonding straps added), and clean the brown feed wires and battery terminals. The popular bulletproofing upgrades are converting the points distributor to electronic ignition (Pertronix), and swapping the old 16ACR-style alternator for a modern higher-output internally-regulated alternator so the gauges and any added electric fan have reliable current. Note: with electronic ignition, never crank or run with a plug lead off — it can fry the module.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Moss Motors 736-040 engine-to-chassis ground strap

    replace a corroded, broken or high-resistance engine ground strap confirmed by inspection or voltage-drop testing Fitment/availability: 1968-1976 Triumph TR250/TR6 engine-to-chassis ground path per retailer fitment Fitment/availability: …

    Moss Motors
  • British Wiring BC58 battery grounding strap

    replace a damaged or high-resistance battery ground cable after voltage-drop diagnosis Fitment/availability: Triumph TR250 and TR6 battery negative-to-body ground branch Fitment/availability: In stock with quantity control live when revi…

    British Wiring

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$150 - $1,200

Research This Issue

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Community Reported
High ConfidenceVerifiedReviewed Jun 2026

On the 1969-1975 Triumph TR6, european-market TR6 PI cars use the Lucas mechanical petrol-injection system, fed by a Lucas high-pressure pump. It is notoriously difficult to set up and live with: hard hot-starting after standing, blocked injectors, throttle-shaft wear that wrecks the mixture balance, and a pump/metering unit that ages poorly. Early TR5/TR6 PI tanks also lack an anti-surge reservoir, so on a tight left-hander below a quarter tank the engine fuel-starves and stumbles. This is the single most temperamental system on the car for a restorer.

Common Symptoms

  • Won't restart when hot after standing
  • Rough idle and uneven full-throttle from throttle-shaft wear
  • Stumble/cut-out on left turns with under a quarter tank
  • Blocked injector causing a dead/weak cylinder
  • Failing Lucas high-pressure pump (noise, low pressure)

How to Fix

Two proven paths. Keep-it-original camp: rebuild the metering unit and injectors, replace worn throttle shafts, fit a modern Bosch high-pressure pump conversion kit (Revington TR) in place of the failure-prone original Lucas pump, and install a tank with the correct anti-surge reservoir to cure cornering starvation. Reliability-first camp: convert to twin Stromberg/SU or Weber carburettors (the US-spec setup) for far easier tuning and dependable starting, accepting a small power trade. Either way, address the anti-surge tank so the car doesn't cut out in corners.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Rimmer Bros 214347BOSCH Bosch-type TR5/TR6 PI fuel-pump conversion

    replace a pressure- and current-test-confirmed failing Lucas high-pressure pump with the matched conversion Fitment/availability: Lucas mechanical-PI Triumph TR5/TR6 pump branch; confirm CP/CR plumbing, 105-110 psi system requirement, PR…

    Rimmer Bros
  • Rimmer Bros 157913 new Lucas-PI injector

    replace an individually confirmed blocked, leaking or out-of-spec PI injector Fitment/availability: Triumph TR6 Lucas mechanical-PI injector branch; quantity required is six for a complete set, but replace only after spray and opening-pr…

    Rimmer Bros
  • Revington TR 312359XALK 54-litre aluminum fuel-tank kit with PI anti-surge reservoir

    correct reproduced low-fuel cornering starvation caused by an early tank without an effective anti-surge reservoir Fitment/availability: TR4/TR4A/TR5/TR250/TR6 including mechanical-PI TR6; for the TR6 branch confirm body/tire clearance, …

    Revington TR

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$400 - $3,000

Research This Issue

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Community Reported
High ConfidenceVerifiedReviewed Jun 2026

On the 1969-1976 Triumph TR6, the TR6's small 16 x 16.5 in radiator and engine-driven fan leave little cooling margin, so cars run hot idling in traffic and in hot climates, especially once the original brass core is partially silted up or the timing/mixture isn't right. The factory fan moves little air at idle, and a clogged or tired radiator pushes temperatures into the danger zone in stop-and-go driving.

Common Symptoms

  • Temperature climbing while idling or in slow traffic
  • Coolant loss / boiling over in hot weather
  • Runs cool on the move but heats up when stopped
  • Old/silted brass radiator core
  • Engine-driven fan moving little air at idle

How to Fix

Bulletproof the system as a package rather than chasing one part: refresh the basics first (verify the thermostat opens, correct belt tension, healthy water pump, full flush) then fit an aluminum cross-flow/high-capacity radiator (Wizard Cooling, US Radiator) sized for the TR6, and add a thermostatically-switched electric cooling fan (e.g. Hayden/Spal ~14 in) which the community reports drops idle temps roughly 6–10°F and removes the parasitic drag of the engine fan. A 13-blade 'tropical' fan is the cheaper interim fix if staying engine-driven. Always confirm ignition timing and mixture, since a lean/retarded TR6 runs hot.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Wizard Cooling 99003-101LP aluminum radiator with 16-inch electric fan and electrical kit

    replace a flow-test-confirmed inadequate radiator and add controlled idle airflow on the early/mid cooling layout Fitment/availability: 1969-1974 Triumph TR6 manual-transmission cooling branch; retailer also lists 1968 TR250, and install…

    Wizard Cooling
  • Wizard Cooling 99004-101LP aluminum radiator with 16-inch electric fan and electrical kit

    replace a flow-test-confirmed inadequate radiator and add controlled idle airflow on the late cooling layout Fitment/availability: 1975-1976 Triumph TR6 manual-transmission cooling branch; confirm installed thickness, fan clearance, pola…

    Wizard Cooling

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$300 - $1,500

Research This Issue

GoogleRedditYouTubeNHTSA
Community Reported
High ConfidenceVerifiedReviewed Jun 2026

On the 1969-1976 Triumph TR6, the TR6's semi-trailing-arm independent rear suspension relies on soft rubber bushings at the trailing-arm pivots and fixed (non-adjustable) factory brackets. After decades the rubber perishes and collapses, letting rear camber and toe wander under load, which gives the car a vague, darty rear end, uneven inner-edge tyre wear, and clunks. The fixed factory bracket also can't correct the excessive negative camber a sagged car develops, and stresses the inner mount (a contributor to the trailing-arm bracket cracking restorers see).

Common Symptoms

  • Vague or darty rear end under power and over bumps
  • Excessive negative rear camber / inner-edge tyre wear
  • Clunks from the rear trailing-arm pivots
  • Collapsed or cracked rubber trailing-arm bushings
  • Rear toe/camber that changes as the car is loaded

How to Fix

The standard bulletproofing rebuild is polyurethane trailing-arm bushings (SuperPro/Prothane) in place of the worn rubber for a firmly-planted rear without a harsh ride, combined with Goodparts/Richard Good adjustable trailing-arm brackets so rear camber can actually be set correctly instead of living with the factory's excess negative camber. Do it alongside fresh shocks/springs and a full inspection of the trailing-arm mounts, since the same area is the chassis crack/rust hot-spot. Properly set up, owners report flat, predictable cornering and even tyre wear.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Moss Motors 683-016 SuperPro polyurethane rear trailing-arm bushing set

    replace confirmed perished or excessively compliant trailing-arm pivot bushings Fitment/availability: 1968-1976 TR250/TR6 IRS trailing arms, one four-bushing set per car; confirm the mounts, studs and arms are structurally sound Fitment/…

    Moss Motors
  • Good Parts 059 adjustable trailing-arm bracket kit

    correct measured rear camber after worn parts and structural damage are addressed Fitment/availability: Triumph TR4A/TR250/TR6 IRS, set of four; adjusts camber only and requires sound frame mounts plus separate toe adjustment with shims …

    Good Parts

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$250 - $1,400

Research This Issue

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Community Reported
High ConfidenceVerifiedReviewed Jun 2026
NHTSA Recalls4 recalls

FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY

Campaign #74V11100016/07/1974

VISIBILITY:REARVIEW MIRRORS/DEVICES:EXTERIOR

Campaign #73V05500007/03/1973

VEHICLE SPEED CONTROL:LINKAGES

THE POSSIBILITY EXISTS THAT THE THROTTLE MECHANISM MAY FAIL TO CLOSE EFFICIENTLY. THIS COULD CAUSE THE DRIVER TO LOSE CONTROL OF ENGINE SPEED.

Campaign #78V01400020/01/1978

EXTERIOR LIGHTING:HEADLIGHTS:SWITCH

THE HEADLAMP SWITCHES MAY MALFUNCTION ON THE INVOLVED VEHICLES. SHOULD THIS OCCUR, LOSS OF HEADLAMP AND TAILLAMP ILLUMINATION MAY RESULT. SWITCH BREAKAGE WILL ONLY OCCUR WHEN THE SWITCH IS BEING TURNED ON OR OFF.

Campaign #78V013000
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Frequently Asked Questions

What are the most common Triumph TR6 problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1972 Triumph TR6 has 6 documented issues. The most frequently reported are: Crankshaft thrust-washer wear and excessive end float, Cracking differential mount (studs rip out of the frame), Lucas charging and electrical gremlins (corroded earths, weak alternator). Of these, 2 are rated critical and should be addressed promptly.

Is the Triumph TR6 reliable?

The 1972 Triumph TR6 has 6 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 2 issues are rated critical: Crankshaft thrust-washer wear and excessive end float and Cracking differential mount (studs rip out of the frame). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Triumph TR6 problems?

Repair costs for known Triumph TR6 issues range from $60 to $3,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Crankshaft thrust-washer wear and excessive end float, typically costs $60-$3,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1969-1976 Triumph TR6 Crankshaft thrust-washer wear and excessive end float?

The straight-six uses semicircular (half-moon) crankshaft thrust washers at the centre main rather than full-circle thrusts, and the soft lead-indium face wears quickly. As they wear, crankshaft end float grows beyond the 0.006–0.008 in spec; past about 0.015 in the coating is go… Repairs typically run $60-$3,500. Severity: high.

What is the 1969-1976 Triumph TR6 Cracking differential mount (studs rip out of the frame)?

The diff is hung from the frame on a forward 'mustache' bracket and rear mounts. The forward differential mounting points are prone to cracking; the right-front point fails first because it carries the most torque load. As the mount works loose the crack propagates and, if ignore… Repairs typically run $150-$900. Severity: high.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.

20/01/1978

Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.

What is the 1969-1976 Triumph TR6 Lucas charging and electrical gremlins (corroded earths, weak alternator)?

Like most British cars of the era the TR6 runs Lucas electrics with bullet-connector harnesses, a 16/17ACR alternator and lots of in-line earths through the body and bulb holders. Decades of corrosion at terminal blocks, the positive battery cable connections, the brown feed wire… Repairs typically run $150-$1,200. Severity: medium.

What is the 1969-1975 Triumph TR6 Lucas PI petrol-injection: hot-start failure, blocked injectors, fuel surge?

European-market TR6 PI cars use the Lucas mechanical petrol-injection system, fed by a Lucas high-pressure pump. It is notoriously difficult to set up and live with: hard hot-starting after standing, blocked injectors, throttle-shaft wear that wrecks the mixture balance, and a pu… Repairs typically run $400-$3,000. Severity: medium.

What is the 1969-1976 Triumph TR6 Marginal cooling / overheating in traffic and hot weather?

The TR6's small 16 x 16.5 in radiator and engine-driven fan leave little cooling margin, so cars run hot idling in traffic and in hot climates, especially once the original brass core is partially silted up or the timing/mixture isn't right. The factory fan moves little air at id… Repairs typically run $300-$1,500. Severity: medium.

What is the 1969-1976 Triumph TR6 Perished rear-suspension bushings causing rear camber/handling vagueness?

The TR6's semi-trailing-arm independent rear suspension relies on soft rubber bushings at the trailing-arm pivots and fixed (non-adjustable) factory brackets. After decades the rubber perishes and collapses, letting rear camber and toe wander under load, which gives the car a vag… Repairs typically run $250-$1,400. Severity: medium.