For whatever reason, I don't think the exhaust test is related. I mean, it should be negative but I think the problem is in the cooling system. Fans coming on appropriately? Working as they should? Blockage in the tubing/hoses/radiator? collapsing hose somewhere? Air bubble? Did you remove the thermostat? I'd still look at the water pump. It might be moving some water to make the hoses warm as you'd described but maybe not enough...
Do a coolant pressure test and see where water comes out.
Gotta be a head or block problem.
Or, you still have some of the original coolant in there that already has combustion gasses in it.
Maybe a cracked head? But how the problem came about doesn't seem to point towards that to me.
whatever it is, you'll find it!
Yall think like i do! Those potential causes have been vetted... I will get the heads off again this weekend. They are going to a reputable local machine shop for inspect, water test, flatness check and (at least) surfacing.
Aint motorsports fun!
I was having similar issues in my E36. Not the cooling system, not the headgasket, no cracks in the head. Turns out the [replacement] head was dented slightly.
buzzboy said:I was having similar issues in my E36. Not the cooling system, not the headgasket, no cracks in the head. Turns out the [replacement] head was dented slightly.
dont think i will get that lucky!
dropped off the heads yesterday. its a small, two-man operation. no signs on the door. just all sorts of V8-goodness inside.
no guess as to when i will hear from them. which is okay. this is my least favorite time of the year to drive the kart (in florida). plenty of other things that need attention in the mean time.
much to my surprise, the machine shop just called. the heads are done.
they did leak during the water side pressure test. even after being cleaned they couldnt find any imperfections visually, one head did require a bit more of a cut, he said a couple thou, more than the other to get to flat. they did a routine valve job. they didnt see anything they thought would cause my symptoms. hoping like hell it was the one head...
it will be this weekend before i have a few hours to get it back together... still way sooner than i expect, but with less certainty than i was hoping for....
Wait, the heads leaked. The techs didn't find anything. What did they do to make it not leak anymore?
wvumtnbkr said:Wait, the heads leaked. The techs didn't find anything. What did they do to make it not leak anymore?
ugh. no, thats me not being able to type/think/reread.... should be "they didnt leak...."
so no smoking guns.
We all need proof readers, the trouble is AI cannot read our thoughts, only our output, so back to the original computation problem!
i got the heads back. They look like new! machinist said they were in desperate need of a valve job. they, of course, didnt leak when they pressed up the coolant side. they are pretty convinced that there isnt a thing wrong with the heads. which makes me pretty convinced of that too.
While I still don't think it's related to the head gasket, have you gone over the block to ensure that the head gasket surface is 110% flat? That the cylinders aren't cracked???
I got the top end reassembled again this past weekend. Also this weekend i replaced my infrared thermometer, should have done that a long time ago.
I drove the kart down the street to get it warmed up, the temp gauge never stops moving from lower peg to over temp peg, it near continuously creeps across the range. After pulling back into the driveway, i whipped out the thermometer. The gauge was reading 250-260deg and the expansion tank was puking its guts through the 20lb cap.
However, the hoses and radiator were essentially ambient outside temp, ~100deg. The thermostat housing was ~220deg. So, the water in the engine was certainly boiling but the rest of the cooling system wasnt hot.
While at the machine shop, talking to the engine builder/owner, we discussed the symptoms. Thou the positive combustion/exhaust in the coolant test is inexplicable, the symptoms sounded like coolant vapor lock to him.
Between the latest observation and what he had to say i started to rethink the cooling system. Of course, none of this still makes any since, considering i pulled the thermostat at the challenge and it still overheated and this arrangement had run just fine for a couple months prior. There is no single variable to point too.
But..... i have to run this to ground before i pull the short block which is the only remaining thing to do..
What could be happening is the thermostat is somehow stuck... Seems improbable, but who knows. that would explain what i saw on saturday. Compounding that, when i converted to kart 2.0 i eliminated the small motorcycle radiator i had located on the passenger side firewall. It had been plumbed like a heater core and tied in the cyl head 'steam' lines - which are the engines coolant natural high point. On 2.0 i tied the 'steam' lines together with a T and had a 1/4 npt plug to use for bleeding. The lines were then plumbed to the heater return side of the water pump and the heater feed bung was plugged. Again, though improbable, i think this arrangement could potentially introduce an air pocket into the engine when the thermostat is closed.
So... i have ordered a pieces to swap where the steam lines tie into the water pump and a new thermostat. If they get here early, i should be able to try the new arrangement today.
In reply to Go_Gators (Forum Supporter) :
Take the water pump off and verify that the impeller still has vanes. Twice in the last 1/2 century I have seen such a failure, with different root causes. One steel stamped impeller corroded away, and a plastic impeller melted due to the previous coolant loss overheat. Your system used to work, and did not vapor lock, so the loss of flow is something else.
TurnerX19 said:In reply to Go_Gators (Forum Supporter) :
Take the water pump off and verify that the impeller still has vanes. Twice in the last 1/2 century I have seen such a failure, with different root causes. One steel stamped impeller corroded away, and a plastic impeller melted due to the previous coolant loss overheat. Your system used to work, and did not vapor lock, so the loss of flow is something else.
Thats fair. i will pull it when i swap the lines/stat. I have kinda ruled it out since i replaced it in 2019 and with the rad hoses off, i can hear it move through the remnant water when i hand spin it...
I'd be looking at the removal of the motorcycle rad for the current set up. When I removed the heater core from the E21 and just used a hose to route that coolant where it needed to go, the gauge indicated higher temps. It didn't create a bubble and didn't overheat but the hose itself seemed to be heat soaking as it got no airflow at the back of the engine along the firewall.
Wrapping it in DEI shield did the trick for me but I also purchased an in-line finned cooler that I was going to try as a second option. Maybe that could work for you? It does seem that you've either go no flow or a bubble though considering how quickly it overheats.
In reply to Go_Gators (Forum Supporter) :
if the LS cooling system is like the LT that preceded it, you can't just dead-head those steam ports into a T with a bleeder. You have to let them flow. i'm not sure how the heater portion of the water pump is plumbed but is it possible that the return/inlet doesn't flow if the supply/outlet is capped?
step 1 from here is to put it the plumbing back the way it was on Kart 1.0 to confirm or deny whether that is the cause.
yea, thanks guys, it currently kinda neither of those scenarios...
The lines near the red highlight are my steam lines. the one going from the T up, towards the intake goes to the front steam line. The one going down/back goes to teh rear steam line and high point bleed.
Think my error in regard to this arrangment is that they T into the pump on the "from" the heater core port. Probably should be on the "to" the heater core port judging by common arrangements online. This would align that flow with teh main flow from the engine to the radiator.
You cant see it from this pic, but there is a plug in the "to" the heater core port, located next to where the steam line currently ties into the pump. its common to block the heater core ports off entirely, so i dont that is inherently an issue..
Amazon, as they predicted, didnt get the latest thermostat to me till 630pm, so i didnt get a chance to install, bleed and run the kart...
but... i did pull the pump, its mint.
and the kids and i experimented with the old thermostat in a pan of near boiling water...
it cycled just fine...
i swapped the steam line to the other heater port. so really, when i install the new thermostat today, the steam line change is really the only change i am testing.. . not feeling very optimistic.
Collapsing hose on the suction side? I have seen a hose that collapsed internally while it appeared normal from the outside. The steam line change make sense, a lot of it in theory at least.
"So please, a little respect, for I am Constanza, Lord of the Idiots."
One of my favorite quotes... Seems applicable at the moment.
I put the cooling system back together yesterday after, another activity i could do with my eyes closed. This time i ran the steam lines to the heater core input side of the pump. Visual of the miniscule change below...
Refilled it with water, bled it. Drove it around the hood... temp gauge stayed in teh happy zone. brought it home, let it idle for ~10 mintues. Ditto. Took it out on the four-laner for a couple hits, Ditto. Brought it back home and let it sit and idle some more. Ditto.
Calling it healed. Not real thrilled with myself. But, i also cannot explain away the symptoms, particularly the exhaust in coolant test results, that i was trying to rectify... either way, going back to beat'in the hell out of it with no regrets.
We've all been there, different versions of the same thing! I'm happy to see this, and I don't think I'm entirely rationalizing to expect it to run harder with the heads freshened.
See you at the next event!
Floating Doc (Forum Supporter) said:We've all been there, different versions of the same thing! I'm happy to see this, and I don't think I'm entirely rationalizing to expect it to run harder with the heads freshened.
See you at the next event!
Appreciate it. looking forward to it!
berkeley yeah! That's a good first post to read this morning.
Awesome news!!
You'll need to log in to post.
