Hey guys, I'm in a predicament and could use some advice! I've been trying to get my '88 Sport Coupe roadworthy again after sitting for a few years, and so far so good, she's gone from being destined for the junkyard to firing right up! But I've run into a bad issue....

Lately I've been having over heating issues, and the car has probably had these issues for a while as the PO had the fan rigged straight to the battery so it constantly runs. Earlier today I ran it around with the fan running and she stayed at 180 without a hitch, but after driving around a bit the car seemed to be losing power pretty bad, as in with the car in gear it would barely move forward/backward. I checked the ATF and it was pretty low, so I added a pint and took it back out. Ran great at first and from a standing start was able to get up on it's feet pretty fast, but I started to overheat and went to park it. Since I hadn't lost power as usual up until this point, I shifted back into gear and there it was, could barely move. I noticed the other day when shifting into Reverse the car shuddered for a second but smoothed out. What do you guys think? Maybe a cable adjustment or something?

The other issue I'm having is pretty bad, when I parked it the second time today I opened the hood to check my fluids, oil was good but smoking out the stick, and a small amount of smoke was drifting from behind the engine. It smelt sweet, and I heard hissing, and that's when I noticed that where my thermostat screws in, there is a small hairline crack that was dribbling a small stream of coolant! Has anyone run into this before, and can it be fixed? Or is my 2.8 in really hot water?

Many thanks guys

 

I did some research and since it's such a small crack, it looks light I might be able to get away with running a Radiator/Block sealer in my coolant. I'm also going to run a radiator flush and put in some fresh coolant bcuz my old looked like junk when it started boiling into the recovery tank and sure isn't helping my overheating problem :P

What do you guys think? What order should I run this all in? I'm thinking radiator flush in old coolant then dump the radiator, install new coolant and run the sealant....

 

with the ATF, you say it was pretty low and added a pint. you need to check the fluid correctly, drive it for a bit to get the fluid hot, check the fluid with engine running in park, then add the correct amount. check it a few times if needed. put some cardboard under your car when you park it, maybe you have a small tranns leak?

are you saying that your thermostat housing is cracked? this part; https://www.carid.com/1988-chevy-cam...-filler-necks/

if so, buy a new one.
your coolant system is under pressure to keep boiling tempuratures down. something like 3 degrees to every pound of pressure. so a 16 lb radiator cap keeps your boiling point around 212F + (16 x 3), or approx 260 degrees. any pinhole, crack, bad cap, etc, brings your boiling point back down to 212F.

i would avoid any "sealer" if can, because its going to coat every surface of the coolant system including your radiator. just do a proper flush. the directions are usually on a bottle of flush from the auto store.

is your lower air dam in place?

fan working ok?

 

I did check the fluid hot, It looked fine cold but after driving a bit it was well below the add mark.

I wish it was that easy, but it looks like there's a hair line crack right where the thermostat bolts into the engine, I'll try to get a picture later today

Lower air dam is in place, but fans are rigged to run directly off of the battery (PO hackjob I need to fix up), Runs fast at first then while driving will slow down. Thank you

 

Sorry for low quality but the crack is pretty evident-This is looking at the thermostat facing the engine, I spray some Tuff Stuff on it to make it easier to see:



Looking down from the upper plenum:



Not a pretty sight

 

Ouch, thats had to many heat cycles lol just get a scrap lower intake manifold and replace it. Is your oil pressure good ? And thermostat new ? What colour are the spark plugs ? Good fuel pressure ? Just wondering why its runing so hot dude ...............

 

Haha thanks dude, I guess that's going to be the best route to take. If I can't find a 2.8 does anyone know if the same part off of a 3.1 will be compatible? Oil pressure seems good, spark plugs look like they're on the rich side but that could just be a leftover from the time I spent getting the car running. I know the car has a high idle in park but in gear she's nice and smooth. It's funny how the car ran at a perfect 180 the other day then later the same day was over heating. I know a coolant flush would help, I'll do that and find a plenum and get back to everyone asap 'u'

 

The lower intake manifolds between 2.8 and 3.1 are the same. I have a bare 2.8 lower intake laying around if you're interested. PM me.

 

Thanks Dave but the junkyards here are usually plentiful, appreciate it though

 

youve got a bad head gasket. Look at the bottom of your oil cap if its white it means your head gasket is about to go just sayin .. Sorry for the bad news but repairing it asap is your best bet

 

Danny, please read the dates of the threads you respond to, this thread went cold in 2017 and I'm betting by now the OP has it sorted......