Removing and installing, checking coolant thermostat — AUDI
Removing and installing, checking coolant thermostat on Audi: factory workshop procedure for engines AAH, ABC, ACZ, AEJ.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📐 9 workshop diagrams for AAH
Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.
📋 Procedure
ABC ACZ AEJ
Removing
Drain coolant => Page
19-4
.
Remove ribbed belt => Page
13-9
.
Remove tensioner for ribbed belt.
Remove left and right toothed belt guard.
Mark direction of rotation of toothed belt. The belt can break if it rotates in the opposite direction when refitted.
Apply load to toothed belt near right camshaft toothed belt sprocket and turn crankshaft to and fro a few times at central bolt of crankshaft toothed belt sprocket.
Note:
This to some extent slackens the toothed belt on the right side, and this can then be pushed forwards more easily.
Pull toothed belt forward slightly on tensioning roller and right camshaft toothed belt sprocket -arrows- - do not pull off completely.
Important
If the toothed belt has slipped off the tensioning roller, the valve timing will have to be adjusted => Installing toothed belt (Adjusting valve timing), Page
13-23
Detach thermostat housing -arrows-.
Note:
The illustration shows the thermostat housing with the toothed belt removed.
Remove oil seal and thermostat.
Installing
Installation is carried out in the reverse order; note the following:
Note:
Replace gaskets and seals.
Before installing, clean and smooth down oil seal sealing surface as required.
Install thermostat.
Installation position:
Vent valve -arrow- faces upwards
Sealing ring to housing
Install thermostat housing.
Important
If the toothed belt has slipped off the tensioning roller, the valve timing will have to be adjusted => Installing toothed belt (Adjusting valve timing), Page
13-23
Push toothed belt towards the rear.
Fit left and right toothed belt guard.
Install ribbed belt tensioner.
Install ribbed belt =>Page
13-12
.
Top up coolant => Page
19-8
.
Tightening torques
Component · Nm
Housing for thermostat to cylinder block · 10
Ribbed belt tensioner to cylinder block · 55
Check coolant thermostat
Heat thermostat in water bath.
Starts to open · Fully open · Opening travel
approx. 87°C · approx. 102°C 1) · at least 8 mm
1)
cannot be tested
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
Ask about my car →Other AUDI procedures
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- Fitting locations overview
- Replacing engine control unit
- Removing and installing upper section of sump
- Servicing valve gear
- Removing and installing toothed belt – Audi · 56 torque figures
- Removing engine – Audi A8 D3 · 41 torque figures
- Removing camshaft timing chain from camshafts – Audi A6/A7 C7 · 38 torque figures
- Installing engine – Audi A8 D4 · 36 torque figures
- Removing and installing camshaft timing chain · 29 torque figures
Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.