Slow87

bone stock 305 lg4. When I first got the car it ran super cool! It would heat up to 185 then drop to 160 and stay there. I replaced everything with the exact same part. For some reason now the temperature just keeps climbing! I turn the car off at 140* cause I get scared.

I bought brand new water pump, radiator, radiator hoses,185* thermostat, radiator cap, cooling fans, and the belt for the water pump and the stupid thing is still over heating! I can't figure this out. No white smoke out the exhaust, I'm not losing any coolant and my oil is perfect. I overheat faster on the highway than I do on the street. Only way I can drive around is with the heater on full blast and its literally 100* outside so its no fun.

Any ideas?

1986 iroc z28

how hot does it actually get?

N_da_Mood

I replaced the Oil sending unit in mine last week because of a problem just like this. Runs great now.

Slow87

No clue, I turn the car off once it passes 240*. I doubt it stops there though.


Oil sending unit fixed your problem? What were some of the symptoms of a bad one?

N_da_Mood

Oil pressure was great when I would first start the car but after a while the pressure would be slightly sporadic. But even when I had a good constant oil pressure it would always heat up unless I had the heat on full blast.

N_da_Mood

Now it keeps cool, doesn't even creep up near 190

Slow87

Hmm, I just bought an oil pressure gauge and still have to hook it up. I have to remove the oil pressure sender and replace it with the one for the gauge. I still don't see how that effects the flow of the oil, its just a sensor. Or are we talking about different parts? Can you please send me a link to the part you replaced!

1986 iroc z28

ok, stupid questions, but they have to be asked, lol, do you have your lower air dam? are your fans working? is ur car full of coolant? is the water circulating? t stat good? i know you said all the parts are new, but that doest mean they are working. When do your fans kick on? one more question, did you get the correct rotation water pump?

N_da_Mood

http://www.classicindustries.com/cam...rts/ps207.html

I am pretty sure that is it, I actually had a mechanic replace mine because we could not figure out what was wrong and he said thats what it was, He also said that it does affect the pressure so?? Maybe take it with a grain of salt. But I know it fixed my oil pressure and heating problems and from autozone he got it for about 10 bucks so... It definitely fixed my heating up problem that is for sure.

N_da_Mood

He makes a great point a lower air dam is a must have especially on the highway.

1986 iroc z28

not to sound like a d!ck, but that has nothing to do with the cooling system, lol

One more question for slow87, are you using your stock gauge? if so try using an aftermarket gauge, these stock gauges are known for being waaaaayyy off, lol
my buddies car says 220* and its at 160ish

N_da_Mood

Not to sound like a d!ck but sadly if your car has no oil pressure.. which means that it is not getting enough oil through the engine of course it is going to heat up. No oil pressure means no oil being pumped and that means hotter engine...

1986 iroc z28

the oil pressure sender, (what you posted), does not control oil pressure, unless for some reason it is blown out and its litterally gushing oil out. It tells the gauge what the oil pressure actually is.

N_da_Mood

Like I said grain of salt it fixed my over heating problem, the same problem he is having so advice is advice

Slow87

Coolant is completely full 30%coolant 70%water with a bottle of wet wetter.
Fans are on a switch for right now, they're always on.
I have no clue what the air damn looks like honestly.
Right now I'm using a sunpro water temp gauge.
Everything works and has been double checked.

I'll try out that oil pressure sending unit!

1986 iroc z28

a bad oil pressure sender will either give you a false reading of your oil pressure (too high, too low, or rapid fluctuating sp?), or make one hell of a bad leak, lol

N_da_Mood

http://www.google.com/imgres?q=92+ca...91&tx=91&ty=26

Thats the air dam, It should be underneath the front of your car

1986 iroc z28

you said you have new fans, what are they? what brand, or style? i know some cheap auto parts store fans cant put out the cfm of flow that is required.

1986 iroc z28

yes, this! this is 100% needed at anything above 40mph

N_da_Mood

Slow87

Nope, I don't believe I have ever had one, Still my car ran really cool until recently so I don't think its going to solve all of my problems.

Hey mood, how were you monitoring your oil pressure? do you have a gauge for it in your cluster?

1986 iroc z28

has it recently warmed up where you live, some cars wont overheat untill its, say over 70*? just a thought

N_da_Mood

Ya just the gauge in the cluster but before I replaced the SU the gauge would read zero alot and thats when the temperature would climb over 220. After the SU it has never hit 200. I am not saying that is the answer but that is what fixed my problem, but an air dam really is a must have.

Slow87

I have universal fans, a 14" and a 10" putting out a total of 2400 cfm. I read that's sufficient enough.

1986 iroc z28

is the rad hot on both sides when its overheating? meaning good circulation? Do you have a way of checking the coolant temp in the rad when its hot?

Slow87

I will go to the junkyard and look for an air damn. Hopefully that will help out a little on the free way. I'm going to buy the sending unit, hopefully that helps when I'm at a stand still. It hit 106* today and it's only going to get worse.

N_da_Mood

I bet it is the air dam because it is getting hotter outside, if you cannot find one I have another one I can sell that is just laying around. But I would try the air dam first because of the weather getting hotter

Slow87

Both hoses are firm and hot to the touch. I can pull of the cap and see the coolant flowing in the radiator. I don't have a temp reading gun to read the radiator temp though.

1986 iroc z28

106*? did you mean 206*? either way, not bad imo, thats totally normal?

N_da_Mood

I think he meant the outside temp is 106, thats how i took it atleast

1986 iroc z28

yeah, the laser pointer temp gun, you should see if you can get one, thats what i generally use to check rad temps with, check the rad in the center somwhere and see what the temp is.

1986 iroc z28

that would make more sense, lol

ringo234

my car would get extremely hot waiting at stop lights, and at drive-thru, but driving 30 mph or more it would cool right down. it turns out that the main fan had a bad connection and by wiggling the wires it fixed the heating and it's been about 160* ever since. Just something to check. I also got an aluminum radiator on E-bay. They were called CHAMPION made in China, but it is made well with 3 rows core and is a direct drop-in replacement and cost about $170 if I remember correctly. My has running ever since. Good Luck

Slow87

My car over heats quicker on the highway than it does in heavy traffic.

N_da_Mood

Definitely try the air dam if it is getting hotter on the highways.

84ws6ta

I can't see how a sending unit would fix the oil pressure and cooling. The sending unit is located on top of the block, behind the intake. All it does it does is send a signal to the gauge to display the oil pressure. Oil pressure is created by the oil pump. Low or no oil pressure can cause a build up of heat, but the sending unit does not control that. There had to be something else causing the overheating issue. I would say it's coincidence that when the sending unit was replaced the cooling issue corrected itself.

calamitascamaro

iTrader: (5)

Air Dam.

Slow87

Hey Mood, I'm interested in buying your air damn. No luck at the junkyard today. I found three but they were super busted up.

Gregzz4

Sorry if someone else solved this earlier ...

I gotta tell ya ..
Coming from 23 years of Auto/Industrial/Marine Cooling Systems ....

Sounds like you need the lower air dam for your car

I don't know them all, but I'll say that every camaro, firebird or iroc I've ever run across since the introduction of the "IROC" needs to have the lower air dam or it will overheat at higher speeds. Same goes for the corvettes for that matter

Something everyone should keep in mind is this -
When a vehicle overheats on the hiway, it's due to a lack of water flow - unless it's system requires an uptake of air from a duct or dam of some sort An example is the late 60's chevy van

When a vehicle overheats in the city, it's due to a lack of air flow

It's a hard and fast rule for most cars, so remember it - barring air dams

Overheat city - no air
Overheat hiway - no water

Gregzz4

And, ya, I haven't posted here for awhile, so I guess you'll just have to take my advice with a grain of stop-leak

Gregzz4

Bah, I can't find any info to back up what I wanted to say, so NM

Slow87

Just encase anyone was interested, I did fix my overheating problem. Apparently 2400 cfm fans aren't efficient enough for my 305. Maybe they are with an air damn, but I still don't have one. I bought a dual fan setup off ebay , (2)10" fans with a shroud totaling 4500 cfm. Now my car wont pass 190* , no matter how hard I drive it. Weather today was 107* btw.

1986 iroc z28

glad you got it fixed, nothing worse than an overheating third gen

Slow87

Yeah man, you totally called it with the crappy fans. I got mine from oreilly's. Two 12" fans that are 1200 cfm each. Now I have no clue what to do with them.

1986 iroc z28

yeah ive been down that road before with two crappy advanced auto fans, i threw those things in the trash, lol

69bu

I wish I had read this earlier today. I had my son's car on a lift putting new exhaust on. We had taken the front spoiler off earlier because it was torn up and looked like sh**. While I was working on the exhaust my son took off the air dam because he thought it looked bad hanging down and you could see it without the front spoiler. Well he drives to his girlfriend's house and calls me and tells me that it is steaming and there is a lot of liquid in the overflow. I told him to take it easy when he came home, He drove home and it did the same thing. He said he was only a mile from home when it started heating up so hopefully no damage was done. I thought I would search the cooling section to get some ideas and bam!!! There it is. No air dam. I love the internet. I am just relieved that putting new exhaust on it didn't cause it.