Need internet diagnosis - LO5 trouble. Head gasket?

So my lo5 has been sometimes running like poop when I first start it - but not all the time, but it's been happening more frequently and it's not weather related. When it does it, I'll usually have to restart the car about 3-4 times, then keep feather blipping the throttle until I'm able to keep it running without stumbling onto it's face. Then after about 30-60 seconds of throttle blipping, it'll improve, catch it's stride, and stay running. Some hesitation leaving lights, but it's old and I'm not in a hurry - so I forgive it.

When we pulled up to the restaurant tonight, I couldn't help but to notice that I was having a problem with coolant incontinence all over the parking lot. I popped the hood and there was all kinds of back-sucking, gurgling, slurping-the-bottom-of-the-empty-glass-through-your-straw, racket going on - and the coolant was pouring out from under the cap of the non-pressurized overflow bottle.

Seeing coolant defying gravity and climbing out from the highest point in the system tole me that something was likely pressurizing my cooling system. The coolant level was overflowing, but the top hose had nothing in it when I squeezed it and told it to cough. Crazy, right?!

I was fat and too hungry to mess with it, so we went in and had dinner anyway. After dinner, the coolant level was within the correct range, but the hose was still empty. I was fat and too full to mess with it, so I drove it home anyway. When I got here, it was still making all those same sounds, but no coolant was overflowing and the top hose was still empty.

So, league of unusual gentlemen, I ask you - if your motor was saying "glub-glub-glub-glub-glub-glub" and peeing on the floor, what would you think?

Also - don't ask me about a temp gauge. Fleetwoods don't have one. They only have a "Sorry brah, you just blew your motor" light that didn't come on.

Thank you in advance for your halps.

Peace,
John

Fleetwoods DO have a temp gauge, you access it through the HVAC head. See the how to in the FAQ sticky on the Cadillac Forum.

LO5s are robust, and don't pop a head gasket easily. I think you have two problems. First, it's cap/rotor/ICM/coil/wires time. Your first paragraph is classic HEI SBC ignition issue related. Second, cooling issues point to a bad rad cap and/or bad thermostat.

Thanks Jay.

I did plugs and wires, but they sold me a broken cap and rotor set, so threw the old ones back on and kept on trucking.

I'll swap those 4 things out and report back - but not till sometime next week.

Depending on whether or not that upper hose was very hot or the same temp as the engine bay,Jay is correct about the cap and or thermostat.What does the oil look like when cold and after warmed up?

the LO5 in my 93 did the same things with the gurgling and spewing antifreeze with the top hose being empty when it's thermostat failed.

it also sounds like there is a mild ignition issue like Jay said.

I'm thinking stuck thermostat for the coolant issue.  When you threw the cap n rotor back on did you clean off the oxidation with an emory board or 220 grit?  I used to have to do that on my gen 1 SBC back in the day, right after I set the points and timing (no HEI for me, it was a 1970).

dammit, Pat beat me to it by seconds, lol

The Tbi engines are prone to Ignition module failure (in my opinion) because of the location of the ignition module being within the Distributor, sitting on top of  hot engines. In our cases they sit there for years. Because of the long overhang of the cowl on B-bodies it's holding lots of engine heat in
There's also a thick gasket , like a door seal  at the back of the hood that additionally acts to keep heat under the hood   (once again My opinion)

Common symptoms that I've been through are driving to the store, but no restart when you come back  out, and cutting out, stumbling.  Plus the symptoms you mention.

I have a few spare ignition modules  here John
Unfortunately, I don't have the envelope you sent me with your address on it.
Give me a PM and I'll send you one.

Dave

Haha, thanks Dave, but I'm pretty sure if I look around here for a couple minutes I can probably find every item I need without even going to the store, including the ignition module.

I do appreciate it though.

pull the stat, do the draina flush,.till everything is clear,. check for weeping fuel lines along the frame rail,. might be sucking aiir,.

Nick

By the time I was able to work on it tonight, every parts store was closed so I swapped out the Tstat with a working one I had on the shelf and cleaned up all the contacts on the dizzycap and rotor that was on there. I also worked the climate control magic to show me the engine temp in Farengazoonheight.

It still ran with an occasional miss and took forever to get up to the 195 range where it stayed. I wanted a higher temp, so I decided to take the car for a ride up the block. It bucked and popped so hard and so often within the first hundred feet I turned around immediately. The highest the temp got to was 199 and then it jumped back down to 194/195.

I'm trying not to sweat how bad it ran until I get a new cap and rotor on it, but I did think it was odd that as soon as I shut it off the water level in the overflow bottle climbed right to the top again. Had I started this out with the correct fluid level in there, it'd have overflowed (overflowed or overflown?) again - which has nothing at all to do with ignition drama.

Hopefully tomorrow I can squeeze in the new parts and it'll be happier - because I seriously do not have time for this BS right now.

triple check the firing order, easy to mix up 5+7

Thanks again to all. New dizzy cap, rotor, raddy cap, and Tstat are all installed. It seems to run much better and doesn't gurgle-suck when I shut it off.

I actually think I might have switched 7-2, but it was good to have me be more careful when I put them back on.

I'm glad it's running better, but it would have been nice to have gotten a less sucky Fleetwood if it didn't. Who knows. Maybe I still might.