jamienoel

Just rebuilt my engine (350 TBI) and put in a new radiator and water pump, but it overheats not long after running (maybe a mile) and I have to run the RPMs to 3500-4000 to get it back down to normal and then it's fine after that and runs at normal temp for the duration of driving.

Sorry if this was already covered, but I thought that if there was an air pocket and the thermostat opened, that would take care of it?

Is there something going on that I'm missing? Doesn't matter if the fan is running or not. The thermal switch got busted off and I have to leave the A/C on "max" until I can get a new one. The A/C pump is not hooked up, so it doesn't engage, but the fan still runs.

It scares me because it goes way in the red before dropping. Fluid is fine and it's a fairly new 180 stat.

rallyup91

Jamienoel, that is rather odd. At first I thought that you had a thermostat with too high of a temp rating, but then I saw that you have a 180 and thats fine. If I were you I would look into replacing the temp. sensor. It might be messed up and is giving you a false reading on your temp gauge.

KnightmareCS

iTrader: (7)

The thermostat opening does not remove an air pocket. If anything it allows air to circulate.
You need to start the car with the rad cap off. Then watch the level. If you have air, coolant level should go down once the tstat opens. Let it run for a bit and fill as needed. Then fill your overflow tank.

jamienoel

It's brand new since the original got busted, which is ironic because of switch suffering the same fate. I had a Buick that did the same thing.

That's what I did the first time. The coolant level dropped when the tstat opened and after it was topped off, I poured some in the overflow, but before that happened it was in the red. It didn't go in the red today, but went close.

Checked the levels in the radiator + overflow and they are normal.

I'm going to try the "hill trick" and see what happens. If that doesn't help, it's getting another thermostat.

8t2 z-chev

Sounds like a "bypass"problem-thermostat not opening
when it is supposed to because no coolant flow past the
wax chamber,revving the engine might increase the
pressure on the thermostat enough to squeeze some
hot coolant past and heat it enough to open...
Could drill a hole of around 1/4" in the thermostat
flange to let a little coolant flow past the thermostat or
fix the "bypass"flow problem.

jamienoel

What could be causing a bypass flow problem? Air in the system?

Ozz1967

iTrader: (4)

Make sure you turn on your heater on HI when you "burp" the radiator with the cap off. This makes sure the coolant circulates through the entire system heating/cooling system. When I changed my water pump the water level "dropped" at least three times before I had it topped off enough.

jamienoel

It's going to the notch just below the red now and then dropping now.

With the 180 and colder temps, it's been running just below 220 and sometimes right at 220. Goes slightly above 220 on a good 1/2 - 3/4 mile hill.

I'm taking it to my uncle's tomorrow and will try your suggestions.

Strange that I've never had to do all this before when the system was drained.

Ozz1967

iTrader: (4)

Does it go steady or do you get spikes in the temp...short term blasts that go upto the red...then come back down....then shoot back up, then come back down? That's a direct indication of a bubble in the coolant system.

Also, I know that my Jet fan switch tells my fan to turn on at 195*...my gauge reads over 220* when the fan turns on. I'm more likely to depend on my 2 year old fan temp switch than my 26 year old gauge. Just some food for thought.

jamienoel

First start of the day or after the car has somewhat cooled, the temp will steadily climb close to the red (next notch down) and stay there for a minute and then quickly drop to normal. (just below 220) At least that seems to be the normal now with the new temp sender.

After it's down to normal, it pretty much stays there if you are not going up hills and then it moves slowly to 220 or just above. Once you are back on level roads or going downhill, it usually works it's way to just below 220.

Everything I mentioned is with the cooling fan ALWAYS running until I can replace the switch that was damaged when the engine lift fell over. Until then, I'm keeping the A/C switch on Max. The compressor is disconnected so it doesn't engage, but the fan still runs. I'm going to get a switch very soon, but the dang thing totally broke me rebuilding it because of all the troubles I ran into.

I'm also wondering if the new aluminum radiator has anything to do with the majority of the different temps I'm seeing? The 3 core brass could keep the engine cooler than I really wanted in the winter, but it deteriorated too far to keep doctoring (soldering) the new leaking spots.

Ozz1967

iTrader: (4)

With the fan off, the temp should settle just below the 220* when you drive on the highway/freeway. The temp spikes high at first until the thermostat opens, which will drop your temp down. All in all, it sounds like the system is working like its supposed to. Just get that switch installed and you are good to go. also, my bet is that your gauge, like mine, isn't exactly accurate.

KnightmareCS

iTrader: (7)

Simple suggestion, change the rad cap. Wouldn't hurt to.

jamienoel

I took your advice, but unfortunately it didn't change. However!!! The old cap/spring was pretty worn out because of how easy it twisted on compared to the new same brand cap. (Stant) The rubber seal was also badly indented, so I'm VERY glad you suggested it!

The new sensor/sender does act a little different than the original 20 year old sensor. It doesn't read as low when it's cold outside after warm-up and tends to read warmer now when going up hills, (over 220) but then this is a new aluminum radiator. Do they run much warmer than the brass? I would love to have an accurate external gauge to monitor for awhile.

Wish the brass radiators lasted longer, but at least the new one comes with a lifetime. The brass radiator will be getting recycled soon. It was developing too many leaks to justify continued repair.

There is one more thing I've been wondering about.

I can not remember the thermostat ever having a rubber ring seal that the stat goes in, but since the head gasket kit came with one, I used it.

Because it didn't have one before, is it possible coolant was leaking around the outer flange and causing a steady temperature rise? It would take forever to warm up before, but now it's pretty quick. It's also the same thermostat (180) which was put in new not long before the tear down, so it's almost new.

I'm always trying to piece things together and analyze any possible solution when I can, which drives my family and friends nuts! They often call me a Vulcan.

But that makes sense, right? No? Forever to warm up without the seal, quick warm-up with the seal, along with the elevated temp until the stat opens? I dunno... Just an observation.

WHERE'S MY DRILL???

KnightmareCS

iTrader: (7)

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The brass radiators suck. They crack way too easy. Had one in my 82, swapped it for a later plastic one.
I went through pretty much the same swap as you I think with my 83. If you did a 305 to 350 swap, then yea. I did the same, new(er) rad, new hd waterpump, new cts, new temp sender, swapped to E-fans with new fan switch, etc.
I don't know if this applies, but the pump you got, is it the right rotation? Are you running a serp belt? What type of pump is it?
The thermostat, you mentioned an oring. Are you using an oring plus a gasket or just the oring. I don't know what the oring is. I've been using only a gasket.
Anyways, would it be possible to get the problem on video. Like how the temp goes up and drops down, etc? I've found watching the problem easier to diagnose.
Did you get the fan working right?

jamienoel

I'll try to get a vid with the digital camera.

The rubber ring is a flat seal with a slit around the middle of the inner diameter that wraps around the outer edge of the thermostat flange. I never used one before and the extra temp variance was non existent. I'm using both the o-ring and the gasket. I know it would have sealed fine with the o-ring alone, but I didn't want to take any chances.

Here's an identical one at Summit. This is the same thing that came in the upper gasket set.

http://www.summitracing.com/parts/FEL-35710/?rtype=10

The water pump is the correct (brand new) replacement and the coolant appears to be flowing in the right direction.

Here is the water pump at Summit. Note that I only paid $16 for it at Advance because of a coupon code. Dang those are handy!!! This one gives specs that Advance doesn't. I almost got the high flow, but changed my mind after hearing bad things about them for normal use.

http://www.summitracing.com/parts/GMB-130-1620/

Serpentine belt is a rerouted (ironically a 93 VIN: K) truck belt because for some reason it doesn't have a smog pump, but it's routed the exact same way as shown in the technical articles section.

IndyL03

Radiator cap should go with new radiator. rebuilt motor might as well have a new t-stat. prop throttle to elivated rpm and have heater on set to warmest setting, fill with appropiate solution of antifreeze and h2o.
using the a/c as a fan might not help fans usually have more than one setting...

and test cooling by getting some speed ~50mph and if it does not over heat then that points to your rigged fan setup

jamienoel

Stat was just put in a couple months or so before the tear-down.

IndyL03

well for some so important yet cheap couldnt hurt to replace...or confirm operation in a pot of water

jamienoel

I'm going to replace it soon and drill the holes as suggested, but I need to know exactly what position[s] on the flange to put the holes.

I'm assuming one 1/8" hole on each side of the flange just a couple or so millimeters in from the outer rim, or rather a couple or so millimeters in from where it sits on the aluminum?

90 camaro cj

did you put the t stat in the right way? ive seen a lot of ppl put the t stat in backwards

jamienoel

I may be dingy at times, but I do have a high IQ and learn extremely fast!

I'm just joking with you, so please don't take my strange sarcasm seriously tonight, but yes it's in right. Wax chamber in intake side. I'm getting slaphappy, so I think I'll scoot to bed.

I really do appreciate your help and suggestions. I'm sure to get it in top running condition soon because of everyone's help!

Happy Christmas to all who celebrate! And to those who don't; Happy Saturday!

jamienoel

Here we go again.

The radiator fan motor is going out! It's probably the original 21 year old OEM motor, so perhaps it's due?

It started sounding terrible and it appears the front bearing is going out because it can be wiggled with a slightly noticeable clunking sound and a scraping sound when turned by hand.

I'm pretty broke right now, (no, I'm extremely broke right now) so the only thing I can buy is the Advance Auto fan (PN: 35656) because with a secret coupon code, I can get it for $19.19 plus tax.

Has anyone used this motor? It has a lifetime warranty, but I think I would carry the old one around as a temp backup just in case.

I'm working on a plan for a low oil pressure warning system, but will have to wait until I have some extra funds to make it happen. My immediate concern is that my car doesn't overheat and blow a head gasket.

Thanks!

jt92

Did you car come with the twin fans or the single? If it has twins I have an extra set from donor car I could send you.

jamienoel

Unfortunately it's the single fan version.

I do thank you for your generous offer though!

I'll just have to get the Advance Auto generic model for now and hope it lasts awhile. They must think it's good if it has a lifetime on it.

KnightmareCS

iTrader: (7)

The generic one should be fine with the lifetime warranty. Replace it whenever it blows. If anything, you can find a fan at a u-pull-it.

jamienoel

That reminds me about our local U-Pull-It. My transmission hasn't been acting all that great for some time now. During the warmer months, it doesn't like going in or staying in 4th unless I'm running about 55-60+, so just before fall I called to find out how much an automatic transmission would cost and the guy said $100 with the old one as a core.

He asked what it was for and I told him an 89 Camaro and he said they no longer carry those in the yard and you have to buy ALL the parts from their full service used parts warehouse, which of course they charge twice for. The 700R4/4L60 can be swapped from any model vehicle that used it, so this guy must not be too knowledgeable about transmission types used in different vehicles, although I've done tons of reading to find out everything I can about my car. I asked him about any late 80's or early 90's Chevy trucks with automatics, but he didn't know if they had any. I didn't think to ask about a Caprice.

I guess I would have to do a cross reference to see what other vehicles used this particular fan motor or they will charge me extra for them pulling it since they no longer have Camaros in the main yard. I would love to change to the dual fan setup, but it can wait. Right now I just need to keep it on the road.

The generic replacement motor is cheap, so I have no choice but to go with it for now. The brand listed is "Factory Air" radiator fan motor. Never heard of them.