gta_knight

Then right at the end, hot hot hot !

I took the car out for its first real good run out today, an 80 mile round trip to a show and back, i set off early this morning and it ran great, the temp was at a steady 190 going down the motorway at about 60mph, it would maybe go up or down a degree or two if i sped up or had to slow down etc (ive got an aftermarket digital temp gauge which i know to be very accurate)

Even when i pulled off the motorway and dropped down to 30-40mph it went upto about 195 and seemed nice and steady, no problems at all.

Going all the way home was fine too, However when i was 5 minutes from home in stop start traffic it started getting warmer as it does, so i turned the fans on as i have both dual fans on a switch so i can turn them on before it hits 220 or whatever the stock setting is to kick them on, i dont like the car getting hotter than 215 so i always turn the fans on if it gets to 200

But for some reason the temp just wouldnt seem to come down, it was coming down a bit then it levelled off, then started going up again so by time i got outside the house with the fans still running it was sitting at 230 according to the gauge !

I opened the hood but it wasnt boiling over thankfully, i could hear coolant around the intake and the top of the rad, i couldnt tell if it was bubbling or just sloshing around a bit as i had literally just switched the engine off.

I cant keep driving the car like this as it makes me nervous as hell ! the 5.0 engine used to sit lovely and cool all the time, i rarely had to switch the fans on.

Its a re-gasketed 350 TPI engine, new water pump, new radiator, hoses were new last year on my 305 so i re-used them, its got a 160* stat, thats obviously working as i got hot air through the heater and all hoses get hot etc etc.

I havnt changed the air damn, ive got the short style one which has always been great, does the 5.7 need more air at lower speeds or something ? i cant think what else it could be just getting stuck in traffic, but surely the fans should bring the temp down a lot more than what it did tonight.

Ive got my one big show of the year this weekend which is a 150 mile drive just to get there so im sort of crapping my pants now unless i can figure something out over the course of the week.

formula1LE

iTrader: (3)

Again....the good ole non-shrouded TPI fans not doing their job. I will respond by saying that IMO and from experience, GM should have fully shrouded the fans like they finally did with the 93-up Fbodies. The stock fan motor are a good design but with GM not fully shrouded them they just don't perform as they should.

gta_knight

hmmm, i never had any problem with the 5.0 engine though, same fans, i just bolted them onto my new radiator, they used to bring the temp down fairly quick if i turned both on.

Ive just ordered a 180 degree thermostat, thats 3 people that have said a 180 is better for the TPI and will regulate better ? worth a shot

formula1LE

iTrader: (3)

Seems odd because with the 160 stat, that just means the engine should take awhile to warm up as the coolant is flowing a lot more than usual at lower engine temps-this could be problematic @ idle but not so at higher speeds. Is this 350 built a little or basically stock? Stock motors are not going to tax the cooling system much even with weak fan designs but once you step up performance/wise, things can change.
Going to a 180 might help a little, stock is 192-5 I believe tho-trial and error I guess....keep us posted!

gta_knight

pretty much stock. it was stripped, re-gasketed, new valve stem seals, new oil pump, then ive fitted Bosch 3 Injectors, an AFPR set at 43psi, Hooker headers, stainless exhaust

I dunno if the grille i fitted to the radiator support is affecting anything, its like chicken wire so will let loads of air through anyway, the stock cover was like an angled piece of black plastic but it was all cracked and warped



Thats the only thing thats not the same, the fans worked great on the 5.0, i just unbolted them off my old rad and onto the new one, i rarely had to switch them on unless i was stuck in traffic and they would bring the temp down nicely

joshc

iTrader: (1)

My 350 tended to run hot with the stock type aluminum/plastic radiator.
I installed a Champion all aluminum rad and it more or less stays right at the opening temp of the thermostat.

dixie wrecked

iTrader: (6)

Any chance your radiator/something internally got clogged? Last truck I bought, drove home and it started overheating because it pissed all the coolant out. All I had was a gallon of sweet tea.. got home but the rad was plugged and HOT.

Hell, I've got a modified 355 designed for mud with a damaged air dam, no heater, stock rad never replaced and a single fan and I almost never get over 180 unless its humid and over 100 out.

gta_knight

When i first start up in the garage it does warm up quite slowly and steadily just idiling there. I dont want to burn money on a bigger aluminum rad if this stock one should be more than adequate, and also because its brand new :/

Its a possibility theres a blockage, but cant see how with the engine being stripped right down, then a new rad, new water pump and pretty much all my hoses are new too, all the hoses get hot so coolant is going round everywhere, and obviously its all fresh coolant too, the level in the expansion tank goes up and down to the correct levels when the car is hot or cold.

Bah ! this is pissing me off now.

dixie wrecked

iTrader: (6)

The stock one should be adequate until ya start modifying it heavily or running it much harder..etc..
There might be gunk in the block or heads, I'm not certain if there's a way of testing it.

I'd say you might have gotten the wrong water pump/spins the wrong direction, but if you've been driving with that one for a while and its just now giving that issue, then that would be thrown out. Its not burning coolant either? No coolant in the oil?

gta_knight

Yeah that did cross my mind as its a new pump, originally bought for an 83 but my friend blew his engine and gave it to me, but its the right one for my engine as its pre-serpentine.

i siphoned out some coolant from the rad tonight, there's little black bits in it, not loads but i think that's just bits of paint from painting the block where i might have forgot to mask something up.

what's the best way to check for water in the oil?

gta_knight

Hi all,

I was away at a show this weekend, i made it there and back no problem, about a 220 mile round trip.

So the car stays nice and cool cruising down the motorway at about 60mph, pretty much bang on 180 degrees.

not far from home i got stuck in some traffic for about 5 minutes which i could see as i approaching so i turned the fans on, but the temp kept rising even with them on and it was hovering at about 210 degrees while i was stationary with the fans on.

once i got moving again the temperature came down a little bit to 200, even going to 60mph again.

So its like once it gets hot, it wants to stay hot even with the fans on ? once i switch the engine off it starts cooling down on its own quite quick. i switched the car off when i got home and it was reading about 210 again, and by time i pulled the car in the garage 10 minutes later it was at about 170.

So im still struggling to figure this out, its fine on the move, heats up quickly if i stop, and the temp doesnt want to come down much even with the fans on.

formula1LE

iTrader: (3)

There is no shroud for the fans and the airflow when moving keeps it cool-that alone proves you need shrouded fans. Like I said, GM had a crappy shroud design for these fans. There is no modern vehicle which runs an electric fan(s) that is "open element" like the older GM stuff.

gta_knight

Hmmm, so better fans then ? the thing is when i had the 5.0 engine in, the fans worked great, i could literally watch the temp gauge come down slowly if i switched them on, and they are the same fans.

gta_knight

I forgot to mention when i changed the thermostat for a 180, i had to drain a bit of coolant to seal it properly, so when i ran the engine with the cap off to top it up and bleed it i noticed the coolant was coming in from the heater hose that goes to the top of the rad, just under the cap area.

Is that right for a non serpentine car ? so it must be going around the block, to the heater matrix, then into the radiator then up through the bottom hose, so when the thermostat opens that also lets hot coolant come into the rad too ?

Ive tried to find a coolant flow diagram for an 87 350 but no luck yet

Hal87

iTrader: (1)

Have you tried turning the fans off after you get out of traffic, see if the temp comes down then? Could the wiring on the fans got reversed when you did the engine switch?

gta_knight

No they are both spinning correctly, i can feel them pulling cool air in through the rad no problem.

I let the car run for nearly 20 minutes just sitting in the garage last night and had the fans switched on constantly and it got as high as 182° so the fans certainly slow the temp rising.

But its always when im driving the car slowly after driving at speed the temp keeps going up even with the fans on, thats the bit i cant figure out.

formula1LE

iTrader: (3)

I think possibly the engine is just experiencing a lot of heatsoak so after running @ speed for awhile then idling for a bit, the engine is still hot enough that coolant temps rise-what temp ranges are the switches? It almost sounds as if you need a lower high temp switch to allow the fans @ idle to turn on a bit sooner. Realize though that this could adversely affect your emissions and fuel economy a bit.

gta_knight

i have both fans on a switch under the dash so i can turn them on whenever i want, and i tend to turn them on if the car gets close to 200° so it shouldnt ever go upto 220, but it does.

Its just annoying that my old 5.0 engine with not many new parts, the old rad etc ran cool as anything and i had the same headers / exhaust on it. i hardly ever had to switch the fans on with that unless i was stuck in traffic and the fans would bring the temp down no problem.