Newish M35 owner - ticking noise & first major repair?

[hook47]

Hey everyone!

I'm the proud owner of a 1970 M35A2 with the LD multifuel engine. She's been a real honey my first few months of ownership. The last owner (now deceased, sadly) took pride in this rig, and every time I dig into a maintenance item I usually find it looks like it was done already.

This weekend I had a gathering with army buddies and of COURSE we had to convoy and see the sites in my '53 M37, 68 M38A1, and of course the Deuce! We had a blast but on the last day ol' "Herc" (the name of my rig minted by the last owner) had her first sign of trouble.

She has developed a slight tick right at the back of the motor only when adding power to the accelerator. When she's settled on an RPM the tick cannot be heard. At first I suspected exhaust manifold gasket, as it seems very typical with my experience in exhaust leaks on other vehicles, but sadly I think it's dead center rear side of the engine, in the head gasket just behind the #6 cylinder. I even think I see just a little smoke when a buddy jumps on the accelerator. She still runs amazing, fires right up, no lost power, no notable oil burn or cooling issues.

Herc does a lot of ranch work like dump runs and picking up hay. I know the right thing is to fix her now, especially before the brutal Wyoming winter, but is there an argument for just ignoring it until it effects power? Also any suggestions on further diagnoses? I'm pretty damn confident it's not in the top end or valve train. Did the old screw driver handle test!

Thanks guys. Oh, here is some pictures of my rides!

 

[davidb56]

spray something around the area and find the leak. exhaust leak isnt bad to fix, head gasket takes a little more work, but at least its a pushrod engine.

 

[Karl kostman]

Hook47 congrats on the Deuce, she looks good! As far as the ticking noise start with the easy things first, I would look hard at the exhaust manifold and gasket. If you have a leak there its going to be to far gone already and your gasket has burnt through. With that said the exhaust manifold is relatively to take off just make sure you lube all the bolts with a penetrating oil for at least a couple days before disassembly. Thats where I would start! Good luck!

 

[ToddJK]

I'd definitely check for leaks with some soapy water. Usually if a head gasket blows like that, it will like to leak either oil or coolant under pressure and the loss of power seems to be random due to the severity of the issue.

 

[hook47]

These are great replies guys, thanks! I'll try the soapy water test first. Now with that should I try blowing air up the exhaust system to look for leaks while the engine is off? I feel like spraying when it's running will just lead to instant evaporation. Or do I hose it down before starting and check then?

I do note maybe just a tad bit of oil seepage around the head gasket? Hard to tell tho. Could just be grime. I made a mess changing those spin on filters!

 

[INFChief]

These are great replies guys, thanks! I'll try the soapy water test first. Now with that should I try blowing air up the exhaust system to look for leaks while the engine is off? I feel like spraying when it's running will just lead to instant evaporation. Or do I hose it down before starting and check then?

I do note maybe just a tad bit of oil seepage around the head gasket? Hard to tell tho. Could just be grime. I made a mess changing those spin on filters!

I’m curious if you hear that noise when the clutch is in or out - or both. Noises are funny because they can originate in one place but and through resonation it sounds like it’s coming from a different place. Does the engine spool right up or is there a lag or hesitation? Is there lag or hesitation when in gear and starting to move?

 

[ToddJK]

These are great replies guys, thanks! I'll try the soapy water test first. Now with that should I try blowing air up the exhaust system to look for leaks while the engine is off? I feel like spraying when it's running will just lead to instant evaporation. Or do I hose it down before starting and check then?

I do note maybe just a tad bit of oil seepage around the head gasket? Hard to tell tho. Could just be grime. I made a mess changing those spin on filters!

Spray some water on it and soap her up real good on a cold engine and fire it up. Even with the air from the fan, a leak will still develop some bubbles, plus a cold engine won't warm up fast enough to quickly evaporate everything before a leak can blow some bubbles.

 

[hook47]

Spray some water on it and soap her up real good on a cold engine and fire it up. Even with the air from the fan, a leak will still develop some bubbles, plus a cold engine won't warm up fast enough to quickly evaporate everything before a leak can blow some bubbles.

Perfect, thanks! I'll knock this out and report back!

 

[hook47]

I’m curious if you hear that noise when the clutch is in or out - or both. Noises are funny because they can originate in one place but and through resonation it sounds like it’s coming from a different place. Does the engine spool right up or is there a lag or hesitation? Is there lag or hesitation when in gear and starting to move?

The tick happens regardless of clutch position. It gets noticeable when throttle is added then fades away when the engine maintains an RPM. Zero lag or hesitation in engine response... for now she is still running very strong. If it is a head gasket leak I suspect that may change! No hesitation in gear and she starts to move nice and smoothly. Clutch and transmission feel extremely nice and got a nice fluid change a few weeks ago!