AR164-01 Replacing Heads on 12v V6

[Alfisto Steve]

Work in progress on a 1991 164L so incomplete narrative but we got heads off today and after a couple Aleve, Vino and a goods nights sleep we will soldier on tomorrow and post more on the subject:

Open trunk, disarm alarm siren under right rear carpet with key, disconnect battery and with trunk lid open close latch on trunk lid so you can’t close lid and need key to get back in later (Very helpful if you only have a valet key).
Note: If you don’t have alarm key and alarm is armed you can’t disconnect battery because alarm will go off.

Loosen front wheel bolts slightly. Then jack up front of car with floor jack(s) under jack point(s) on front of sub frame and place jack stands under body jack points under front door areas.

Have magic marker pen and zip loc bags of various sizes to identify and bag up nuts , bolts, screws and hardware as you remove it.

Once you have car safely sitting on jack stands with front wheels off ground, remove both front wheels and both front inner fender liners. If later model 12v V6 with large heater hose return pipe 1” hose hooked to rear of bottom thermostat housing also remove right rear inner fender liner.

Open hood, remove air flow meter and air cleaner box assembly both top and bottom assemblies.

Remove 2 bolts from upper motor mount (dog bone).

Remove top radiator support by removing two bolts holding coil and relay bracket to it, one bolt holding top radiator hose support to it and the 4 bolts holding support to car, Lift support and remove it from a/c hose that is clipped to it.

Remove right side headlight (the one closest to front of engine so you can remove alternator later. There are 5 screws holding headlight frame to body under rubber covering. You have to remove relay holder behind headlight to access two screws for bracket in side of inner fender (if they are frozen you can remove one 8 mm nut that holds that bracket to back of headlight. Disconnect wiring for main bulb and parking/turn signal bulb.

Working through left wheel well with floor jack under transmission differential disconnect transmission mount from transmission case by removing two bolts and nuts on 5-speed models and by removing two bolts screwed into case on automatic models. Slowly lower jack and allow tranny to rest on sub frame (you may have to remove mount from sub frame on automatics to get tranny to lower without binding on mount). This procedure moves front of engine away from inner fender so you can have greater access to remove timing belt covers and later on for extra clearance to lift off rear head.

Now with floor jack out of the way, place big spread of newspapers under engine and radiator areas. Use a large drip pan with a smaller drip pan inside it if you have two and then a large 2 12 gallon container such as oil draining pan to catch the antifreeze as it is time to drain coolant from both radiator hoses and engine block.

There isn’t any drain plug in radiator so you need to remove lower radiator hose from the radiator. Once that has drained down you need to remove two drain plugs from engine block. Plugs takes a 7.8” (22mm) socket on a hinge handle with a cheater bar to remove these brass plugs with sealing washer underneath them. Front one near where dip stick attaches to block and rear one behind oil filter and near rear motor mount attach point.

This rear one very hard to see but to keep coolant from draining into pistons and crankcase you need to try to remove both drain plugs and it helps to drain out crud that builds up around cylinder liners.

Alternate method is to remove bleeder plug from thermostat and apply high pressure shop air to bleeder port.

[Alfisto Steve]

hera are some more pictures of process:

[Alfisto Steve]

Some more of process:

NOTE: SEE THE OIL DRAIN BACK PORT CAP, NUT AND WASHER FROM OIL PUMP SHAFT ON RED TOOL BOX. YOU MUST NOT FORGET TO PULL THAT PORT CAP WHICH GOES IN REAR HEAD AND REMOVE NUT FROM OIL PUMP SHAFT before you even try to remove rear head

[Alfisto Steve]

Moving on with more pictures:

Note use of cylinder liner hold down tools be sure you lock down liners before you turn crankshaft and possibly cause a liner to lift up in block and break the rubber oring on liner that seals coolant water jacket from leaking coolant into oil in crankcase