My '89 Might Be Getting Too Hot to Handle

[DarkRed89Flyer]

I just got my '89 out of the shop on Friday...it was leaking anti-freeze/coolant from the back of the engine. The tech determined that the lower intake manifold gasket was leaking. While replacing the gasket, I had them replace the valve cover gaskets too. After a test drive, it was still leaking, but this time, it was coming from the weep hole in the water pump. So, I had them replace that too, along with a new 195 degree thermostat.

However, since I got it back, I've been driving it to work about 50 miles (round-trip), and I've noticed that when I'm up to freeway speed (65 - 70 mph), the temp goes up to between 220 - 230 degrees. Keep in mind that I'm in Arizona and the high today was 106. Even the B4P booster fan won't bring down the temperature.

I've already checked the obvious: the radiator and overflow tank are full.

I'm thinking that the "new" thermostat may be defective, but if you guys have any other ideas, I'm open to suggestions...

Thanks for your help!

[boomdriver]

Stock radiator?

in Az thats pretty normal. When I lived in Phx 4 yrs ago it was normal to heat up to 230+ with the a/c on in traffic and stay well over 220 when cruising. The high ambient temps are brutal and make air-stream cooling slow if not impossible.

If you believe it cooled better before all this, then the new water pump might be less efficient, the t-stat might be a little more restrictive, so the water does not circulate as well.
Checked for trash between radiator and condensor by pulling the top shroud? thats a MUST before anything else can be blamed for high run temps. Plus, with all that work they now have a high blend of anti-freeze and water....and antifreeze makes the temps go UP> to raise the boiling point. The more water the lower the run temps will be. Too much water and it boils way too soon and allows electrolysis that destroys the aluminum heads and pump inerds.

I have a big all alum radiator now, hi flow pump and my temps will go up to 230 sitting in traffic when there is little fresh air. Thats what its all about....air moving across the radiator to remove heat from the water...the water has to circulate to collect heat for disposal to the fresh air as the car moves.
BTW
that little"pusher fan" up front is as useless as lips on a wood pecker. Its more helpful to the a/c condensor than the radiator...doesn't move enough air to do anything. It actually blocks airflow at lower speeds and causes temps to rise in traffic.

[catbert]

First make sure the mechanical things are right, especially the trash around the radiator. I have used a radiator additive called MotorMax in all my cars for many years. My Vettes and SSR ran hot when I lived in Phoenix over the years, and MotorMax lowered the temps by around 15 degrees. Even the SSR, with the LS2, small grill and engine compartment cooled to a point that I didn't worry abou it anymore.

MotorMax seems to be a well kept secret, but once you try it, you mightbe hooked...especially in Phoenix.

MotorMax is hard to find at retail, but you can Google it, and order online.

[Bob Chadwick]

Isn't the fan on the C4 set to come on at 220? I recall my old friend JRMaroon telling me that was the turn on temp for his late model C4.

[John Robinson]

Since you have obviously had the radiator cap on and off several times in all this. You might want to have it pressure checked. If it is getting weak or has a bad gasket that will not allow the system to get up to the proper pressure than it will heat up higher. As others have said 230 to 240 in heavy traffic is normal. I have found in town if mine gets up to 230 + it helps if I put the car in second gear. I have concluded that with the stock 2:59 axle ratio the water pump is turning to slow. Keeping the rpms about 2000 will make the temp come back to normal faster. Just do not do this for extended periods of time with the automatic because it will start to heat up. This only for a short distance less than a mile. Oh and if the stop and go is really long open the windows and put the heater on high

[boomdriver]

Mine just did all this yesterday....and I consider its performance to be perfectly normal...

ex: drove 10 miles to wallymart & lowes. Temps cruising were 189...with a/c. But the return trip included Wendys (chili, guilty pleasure) and some stop & go. Temps crept up to 220 but not alarming. After some time sitting there staring at the same lite for 5 minutes....I got to cruise again and after 3-4 minutes @ 55-60 temps dropped back to 195 and falling about 1 degree a minute. While at the stop lite even the a/c stopped cooling because it was not getting enough air across the hot condensor. Works again the second that air flow returns (movement) to lower the system pressure.
After the 10 mile drive Its back to 190 and steady.

This is typical behavior and I have an oversize radiator, all aluminum, fans on @ 188-190, hi flow pump and misc other cooling enhancements.
One the flip side I also have a bigger condensor for the r134a conversion and a big outside trans oil cooler in front of the condensor so the radiator gets to suck in heat from 2 other exchangers before it gets a shot at some fresh air.

Its normal. Scary at 230 with nowhere to go and its hot and uncomfortable and thats why we pray for fall weather and spring time when the temps are people and Corvette friendly...

[DarkRed89Flyer]

Mine just did all this yesterday....and I consider its performance to be perfectly normal...

ex: drove 10 miles to wallymart & lowes. Temps cruising were 189...with a/c. But the return trip included Wendys (chili, guilty pleasure) and some stop & go. Temps crept up to 220 but not alarming. After some time sitting there staring at the same lite for 5 minutes....I got to cruise again and after 3-4 minutes @ 55-60 temps dropped back to 195 and falling about 1 degree a minute. While at the stop lite even the a/c stopped cooling because it was not getting enough air across the hot condensor. Works again the second that air flow returns (movement) to lower the system pressure.
After the 10 mile drive Its back to 190 and steady.

This is typical behavior and I have an oversize radiator, all aluminum, fans on @ 188-190, hi flow pump and misc other cooling enhancements.
One the flip side I also have a bigger condensor for the r134a conversion and a big outside trans oil cooler in front of the condensor so the radiator gets to suck in heat from 2 other exchangers before it gets a shot at some fresh air.

Its normal. Scary at 230 with nowhere to go and its hot and uncomfortable and thats why we pray for fall weather and spring time when the temps are people and Corvette friendly...

Boomdriver:

I understand what you're saying about airflow and everything, but I'm having this issue while cruising on the freeway at 65 - 70mph. Granted, the air temp here is high (usually 105+) when I'm on my way home from work in the afternoon, but I don't remember the temps ever getting this hot unless I was stopped at a traffic light. Even in the morning, when it's relatively cool, mid- to upper-70s, I'm still getting coolant temps as high as 205 - 210. I don't feel this is normal for that outside ambient temperature. You suggested that the coolant may be off the 50/50 ratio, but the shop supposedly replaced all the coolant after the work was finished. I'll get out my coolant tester sometime this week and check it. Maybe they mixed it at the wrong ratio, but since I watched them put in the pre-mixed straight from the bottle, I doubt that's it. I'll let you know. The curious thing is that my roommate drives his Toyota Tacoma (I know, don't say a word. I didn't tell him to buy it!) to work and back at about the same times during the day, and once his gets up to operating temp, the gauge never moves, and he doesn't drive on the freeway like I do. His commute is surface streets, with lots of traffic lights, all the way there and back.

To answer John Robinson's suggestion about the radiator cap, it is brand-new. I had it installed when I had the cooling system flushed about a month ago. As for turning on the heater and opening the windows, as John also suggested, my Vette doesn't have a heater.

[John Robinson]

I am seeing the exact same temp as you are on the road. Outside temp 80 to 85 and the car runs between 205 and 210 just like yours. This car was designed to run like this for many reasons. By the way if it really gets to hot or close to it there will be a message on the dashboard by the speedometer saying to check the gauges. Even my 2006 Pontiac runs 215 to 220 on the road. The old school thinking that you had to put in 160 thermostats etc. no longer apply to today's modern cars. The lubricants are so much better than 30 years ago and the engine materials are designed to take the heat.

[boomdriver]

Boomdriver:

I understand what you're saying about airflow and everything, but I'm having this issue while cruising on the freeway at 65 - 70mph. Granted, the air temp here is high (usually 105+) when I'm on my way home from work in the afternoon, but I don't remember the temps ever getting this hot unless I was stopped at a traffic light. Even in the morning, when it's relatively cool, mid- to upper-70s, I'm still getting coolant temps as high as 205 - 210. I don't feel this is normal for that outside ambient temperature. You suggested that the coolant may be off the 50/50 ratio, but the shop supposedly replaced all the coolant after the work was finished. I'll get out my coolant tester sometime this week and check it. Maybe they mixed it at the wrong ratio, but since I watched them put in the pre-mixed straight from the bottle, I doubt that's it. I'll let you know. The curious thing is that my roommate drives his Toyota Tacoma (I know, don't say a word. I didn't tell him to buy it!) to work and back at about the same times during the day, and once his gets up to operating temp, the gauge never moves, and he doesn't drive on the freeway like I do. His commute is surface streets, with lots of traffic lights, all the way there and back.

To answer John Robinson's suggestion about the radiator cap, it is brand-new. I had it installed when I had the cooling system flushed about a month ago. As for turning on the heater and opening the windows, as John also suggested, my Vette doesn't have a heater.

Trust me...
what you see is NORMAL. Its 105 outside ! Your temps are actually pretty friggin good for those ambients...
I lived in Gilbert for many yrs...I know exactly what the weather is like and how hot the car runs. That was BEFORE I installed my big radiator...and mine did well there.

What you have is a case of "old school" fear. A 1970 sbc 350 was at melt down at 200 degrees. That was 1970. This is 2012 and these cars, even those made in the late 80s and 90s are designed to run normally at 220.
There are countless reasons why....but to simplify, by running at 200 your engine will last longer.

[TedC]

I just got my '89 out of the shop on Friday...it was leaking anti-freeze/coolant from the back of the engine. The tech determined that the lower intake manifold gasket was leaking. While replacing the gasket, I had them replace the valve cover gaskets too. After a test drive, it was still leaking, but this time, it was coming from the weep hole in the water pump. So, I had them replace that too, along with a new 195 degree thermostat.

However, since I got it back, I've been driving it to work about 50 miles (round-trip), and I've noticed that when I'm up to freeway speed (65 - 70 mph), the temp goes up to between 220 - 230 degrees. Keep in mind that I'm in Arizona and the high today was 106. Even the B4P booster fan won't bring down the temperature.

I've already checked the obvious: the radiator and overflow tank are full.

I'm thinking that the "new" thermostat may be defective, but if you guys have any other ideas, I'm open to suggestions...

Thanks for your help!

DarkRed89Flyer, Do you feel the engine is running hotter now than it did before the intake manifold gasket swap? Two coolant openings are blocked by way of the gasket. The blocked openings are installed towards the front of the engine.

[boomdriver]

IF the car is getting to 230+ while cruising then there could be trash in the radiator shroud. AT freeway speeds there should be good airflow to get it down to thr 210 range....and 230+ in traffic for those ambients.

I thought you were saying that 210 was too hot...not at all... but 230 on the freeway is a bit high and says poor airflow OR poor water circulation

[John Robinson]

Tedc has a good point in suggesting that something was not done correctly when the new intake gaskets were installed. If in fact they were installed in such a way as to block water passages that would explain the change in the running temp since the intakes were redone.

[89vetter]

DarkRed I was wonder if you ever have any heat soak starter issues (no start when hot) with your '89?

[TedC]

DarkRed I was wonder if you ever have any heat soak starter issues (no start when hot) with your '89?

89vetter, Do you mean extra long cranking time after hot soak? This is the issue I had on my 1988, and it was caused by leaking injectors. When hot, it would restart right up to a minute or two, or after 15 minutes. In between, the injectors were leaking causing an extra rich condition.

[Stonecold C-4]

I just got my '89 out of the shop on Friday...it was leaking anti-freeze/coolant from the back of the engine. The tech determined that the lower intake manifold gasket was leaking. While replacing the gasket, I had them replace the valve cover gaskets too. After a test drive, it was still leaking, but this time, it was coming from the weep hole in the water pump. So, I had them replace that too, along with a new 195 degree thermostat.

However, since I got it back, I've been driving it to work about 50 miles (round-trip), and I've noticed that when I'm up to freeway speed (65 - 70 mph), the temp goes up to between 220 - 230 degrees. Keep in mind that I'm in Arizona and the high today was 106. Even the B4P booster fan won't bring down the temperature.

I've already checked the obvious: the radiator and overflow tank are full.

I'm thinking that the "new" thermostat may be defective, but if you guys have any other ideas, I'm open to suggestions...

Thanks for your help!

Well have you got it figured out yet if not my money is on the thermostat. As others have said make sure you are trash free, which I'm sure you have looked and made sure of that by now. I would start with the cheapest and quickest fix the thermostat go back with a new stock one, I think your water flow is restricted. I hope you put a new water pump on and not a rebuilt the extra cost of new is worth it, if you didn't that's my second point of interest to check. I'm giving the benefit of doubt to your mechanic that he made sure your intake gasket was lined up and sealed properly and the other things he did were done correctly, and not taken anything away from him but everything you had done is pretty simple stuff for a mechanic with the right tools. At highway speeds my car runs 190 and 220+ in traffic that is in TN. Since there have been several members state that they lived in AZ. you have multiple members giving you the same temps of where your car should be at in your area. Keep us posted would like to know what the out come of this is. Good luck