Where is temp sender in older A4?

[jquinn]

I think the A4 in my 69 Cal is an older model. The water path from the pump goes directly into a water jacket rather than into a pipe to thermostat as most digrams online show. I can't even determine if it has a thermostat or where it would be located. I plan on installing the inexpensive water temp gauge from Moyer Marine and don't know which sending unit to buy, or where it is installed. Any tips or advice regarding the old style cooling system would be greatly appreciated.

[lat 64]

If you can snap some photos of the flywheel end of your engine, the top, near the alternator, then we can all gush forth with our sage advice and qualified opinions.
I have a '68 model. My thermostat is in the bump on the cyl.head. See attached.
The hose that enters the t-stat housing from the alternator side is the bypass-circuit. It lets water go over the top (around) the t-stat I think.
Is yours different?

russ

[Marian Claire]

I believe the early models did not come with a T-stat. They used a recirculation loop and valve to control temp. So you may not have one. My 1965 had the Dole T-stat housing added. The housing is on the top, aft end of the manifold. The Dole marking should be easy to see on the housing. Hope that helps. Dan S/V Marian Claire

[jquinn]

All set - Dan is right there is no thermostat...yet

I bought Don Moyer's video explaining the cooling system. What a great instructional tape. I highly reccomend it for those of us who are relatively new to the A4. (I actually have an extra rusty motor that came with my boat, and this video inspired me to go start tearing it down.) I also learned from the tape that my water jacket is original one which was designed for a higher pressure water pump. I may need to step up to a replacement water jacket cover that Moyer sells.

Since I have the early model, the head does not look like the pic that Russ attached. There is just a cross over pipe where from head to manifold where russ's thermostat housing is located. But where water exits the manifold I need to install a thermostat housing and temp sending unit. Right now I don't even have a feedback loop and valve set up from manifold back to pump, so I am always running full cold. (water hose out from manifold simply goes straight back to exhaust elbow). I just don't know how cold until I get the temp gauge installed.

Ran all last season (about 40 hrs) like this so I don't know if I did any damage. Maybe the restricted flow from old water jacket kept it warm enough by coincidence. I will be much more comfortable next year with well controled and monitored temp. Thanks for posting replys so quickly!

Joe Q

[lat 64]

Well whada ya know!
I think now my motor may not be all original. It's suppose to be one year older than yours. Well, I'm glad someone else paid for all the upgrades.

Now that you have publicly stated your intentions you have to follow through

We'll all look forward to seeing a bright shiny engine come spring.

Take lots and lots and lots of pictures while tearing down. This will be your best friend during assembly. For true!

Russ
ps: in Alaska, when you just paint the engine without rebuilding, we call it a road-comission-rebuild.

[Marian Claire]

Jquinn: For the sake of full disclosure. I removed the old T-stat from the Dole housing and with info from others on the forum set up the recirculation loop. My temp sensor is in the fitting between the manifold and the Dole housing. I have good access so I can adjust the valve, as conditions change, to maintain what ever temp I want. This also allows full flow thru the engine and no T-stat to worry about. Dan S/V Marian Claire.

[jquinn]

Dan, apparently you ARE the thermostat. I am actually thinking of doing effectively the same thing. That is, installing a senosr in a tee off the manifold water out, and putting another tee off that which goes to both the exhaust and the pump. I'll put a manual valve before the pump and leave it at the sweet spot, which I will hopefully be able to identify using my new temp gauge. If that doesn't work out, I'll splurge for the Dole housing and thermostat (which I will otherwise do next year).

After viewing the cooling system video, I can finally talk the talk with confidence.

Russ, I'll surely post pictures but don't promise shiny new paint.