Info needed: 1967 M38A1 Lubrication?

[rob love]

Geez Les......I think I may have to start to invoice you for the good (lucky) advice.

[Les Kovacs]

Hi Rob...sure...send your invoice....they are piling up as we speak with so many new parts I can't keep track. So far I have put in a thermostat, had the rad flushed, painted etc...replaced all the fluids, greased all the joints, some hoses, installed a fuel filter before the carb and a second before the fuel pump, tied down the fuel line (it was loose and rattling), fixed the shifter spring clips, replaced the carb to air filter hose, shifter rubber and on and on....in the next week I will replace the spark plugs, points/condenser (will require tips from you if possible) exhaust tip, bell crank repair kit, tie rods....so far this jeep feels like a jet fighter of the 60-70's....for every drive hour, it requires 30 hours of service.

Regards,

les

[Les Kovacs]

Hi Rob...

Saturday I put the newly flushed rad in and installed a 160 degree thermostat (remember it did not have any on taking off thermostat housing).

So, here is what happened on start up......the jeep cranked but would not start....usually it starts first crank....I panicked. Did not know why it would not start. Then, I traced back to what I did before the rad flush/thermostat install.....I installed a second fuel filter on the line underneath the rad....first one was in between the carb and sediment bowl....so, I took off the filter near the carb and left the new fuel filter before the fuel pump.....jeep started first crank!

Question #1.....did the two fuel filters make it hard for the fuel pump to pump fuel to carb or what?

Secondly, once the jeep started, I had my wife sit in the jeep watching the temp gauge....I was watching the open rad to see if coolant level dropped on thermostat opening. (Remember initially on checking the thermostat- there was none on taking the housing off-with no thermostat in the jeep temp gauge never went past 140 F) so now, with an actual 160 F thermostat installed, after about 20 minutes of idling (had to recharge batteries) the temp gauge very slowly went to 180 F-but never moved past 180 F parked in my garage but the coolant in the rad-at the rad cap opening never went beyond 155 F (measured by a new rad temp gauge)-never triggering the opening of the 160 F thermostat....Question...is this normal?

Thanks in advance...

les

[rob love]

1: It should not have. The first filter is on the suction side so does not effect the output pressure. And it does not take 7 psi to flow through the filter. Most likely your system was just re-priming itself or there was some dirt in the checkvalves. A person only blows at about 3 or 4 psi...if you can blow thru the filter, the the fuel pump should be able to.

160 is actually the closing temp of a thermostat rather than the opening temp. Opening temp can be 180 or even higher. So likely that is the temp that the coolant opened, or it has not even opened yet, and so is maintaining that temp with no work being performed. If the thermostat is still closed, then it is just the flow from the bypass hose (maybe a 7/16 hole) that is allowing some level of flow.

Drive it and you should see the temp come down to the 160.

[Les Kovacs]

Hi Rob.....thanks for the quick response....wow what a learning experience!

OK....so here is what happened after an actual 25 min drive at about +27 C and moderate humidity....the temp gauge slowly went to about 185 degrees (temp lingered at around 165 for longest time)and stayed there through the whole drive....after garaging the jeep....I checked the upper rad hose...no pressure so I opened up the rad cap and put in a temp gauge....rad coolant read +155 F....Question....is +185 F normal for average summer drive and why was the actual coolant at +155 F?.....also, why did the new thermostat not open?.....is temp gauge reading dubious?

PS...Temp gauge does not fog up any more since putting in a thermostat.

PS...rad cap is dubious as it is old and I had to put in a rubber gasket that was made out of bike tire inner tube. I have no clue what the PSI rating is!

I am ordering two new rad caps....Kaiser Willys shows that a 7 lb cap is required for the M38A1 but the 1967 CDN military manual states that a 4 lb cap is required.

What's the correct rad cap for this jeep?

Thanks.....les

[rob love]

185 is not normal. It doesn't hurt mind you, but it is not normal.

Any chance the problem is in your gauge or sending unit itself? Perhaps you do not have a problem with the actual coolant.

You could try and pull the sending unit, and replace it with one of those cheapy mechanical gauges from Cdn tire or princess auto and see what reading you get.

Otherwise, you have a circulation problem. One possibility is your antifreeze is over-strength (should be 60/40 mix). You already changed your water pump, so that isn't the problem. And the pressure of the cooling system is to merely raise the boiling point, and does not really effect cooling and flow. But if the gauge is at fault, perhaps that is why the last owner removed the thermostat as an attempt to repair a perceived "overheating" condition.

[Les Kovacs]

Thanks for the prompt response....can you please send me a picture of the temp gauge sending unit?...not sure where it is or what it looks like.....is it still available?

So, I can either use a 4 lb or 7 lb rad cap?

Can you also review the procedure to adjust the fuel mixture (new small additional tail pipe somewhat sooty after only 20 min drive)....what temp does the running jeep have to be...cold or operating temp.....

Thanks!