Overheating

(and I don't mean the world)
my '87 5 speed otherwise std is overheating on continues driving at about 90 Kph (55 MPH). Speedometer is not working but this is driving over 3000 RPM in 5th gear.
It fine at 3K, starting to climb at 4k and got 3/4 up at 5k (where I dropped speed).
First thing I am going to flush the cooling system.
Any suggestions on good stuff for that?
And should I raise the nose or the rear of the car (if any).

raise the nose as far up as you can, remove the bleed screw on the left side of the radiator, open the heater valve, and put a running garden hose in the overflow tank.no bubbles... done deal. when you add coolant, remove the lowest hose on the tank, reattach, and fill with coolant. repeat as necessary to get a gallon in after the car is running with the nose still up.it will bubble and purge, so a few libations will make seem faster than it is.duhhh
mikemo

At 90km/h there is MORE than enough fresh air to the radiator and it should not get hot unless you are driving very hard (eg up very steep mountains in low gears with large throttle openings).

More importantly than rising temperature is if the temperature comes quickly DOWN after it goes up. If it does the system sounds like it is working properly. If it is sluggish to cool, or won't come down at all once it's up there I would lay blame squarely on the radiator. A flush may not be sufficient to clean it out - the only proper way is to sweat the header tanks off and mechanically clean each core. If they are encrusted internally with rust you are going to need a re-core.

The other test of the radiator which is very easily done (as long as you watch your fingers in the fan!) is to use the palm of your hand on various spots on the radiator. If the temperature is consistent wherever you put your hand the radiator is fine. If you get warmer and cooler parts (usually cooler at the bottom) you have a partially blocked core.

Oh - don't forget also that if you transpose the connections to the fan and the fan switch that the fan works as intended - but runs BACKWARDS. Which will counteract the cooling air being forced in by road speed....

My X did the same, replacing old rusty radiator with a new one solved the problem.

My old radiator was not leaking, but it was so rusty and worn, it were not cabable to transfer enough heat from coolant to air...

Duplicate threads

Hi Herzel,

You have two "Overheating" threads right now. I found one in FS&W yesterday and moved it to the WF. So there is one if DF and another in WF right now. Would you mind if I combine them into the thread under WF?

Same exact problem, replaced the radiator...

So Herzel, I'm assuming this is something new...

or tell me if this has been a long time problem. My suggestions would need some clarity to be accurate. Awaiting your answer, but do this as well.

1. State the exact temperatures per your gauge. You can figure that out by dividing the lines into the numbers and assigning them a number. If I recall, midway down from 190 to about the first line is about 185 degrees. Your car should never run higher than about 194 and the fans should come on and DROP the temperature to about 189 and CYCLE.

2. Do you have A/C?

3. Do you have 1 or 2 fans and are they operating? Do you have a bypass switch to operate the fans at will?

4. Send me a photo of the front end of your car as well.

We'll fix this...

This is going into surgery without anesthetics...

OK, to answer your inquiry, Tony.
1. Normally the car runs at 190 deg which is midscale. at times it hoovers a bit up and the fan kicks in, I know because the voltmeter drops some.
at high speed (4k revs in 5th) temp starts climbing. at 5k the temp rose to 3/4 scale which is 225 deg. a At that point I slowed down to 3K and temp dropped slowly.
It was a very hot day about 95 degs.
At the end of an hour's trip water level was up, no loss.
2. I do have A/C
3. I have 2 fans but the second one kicks in with the A/C.

I vad heating problem while driving from Texas to your place. She was overheating badly. At times I turned the A/C on just to add that second fan. At a stopover in Vagas I had the radiator off and chemically cleaned. Had no heating problem ever since.
So I tend to think the cooling system is clogged and before taking things apart I thought i'd flush it, hence my questions.
At any rate' here are some pics of the front:

htfx19 said:

at high speed (4k revs in 5th) temp starts climbing. at 5k the temp rose to 3/4 scale which is 225 deg. a At that point I slowed down to 3K and temp dropped slowly.

Click to expand...

5k in 5th? :shock: I've owned X1/9's long enough to not need a gear calculator to work out what speed you were doing!

On a hot day I would say that your observed 3/4 temp isn't cause for undue worry. When you dropped to 3k (which would be around 100km/h) you should expect temps to return to under the 1/2 mark in around 5 minutes of cruising at that speed in those air temperatures.

When looking to "flush" don't forget that the radiator is the FIRST place for crud to accumulate. Thats because it is filled with lots of tiny tubes that the water has no choice but to go through - effectively making it a filter. If the cooling system is working - but at less efficiency than you would like - pretty much the ONLY place you will find crud is in the radiator. If there is crud all through the system your radiator is completely blocked - which your symptoms don't indicate.

So I agree give the radiator a clean (although as Steve and I have said - a garden hose poked up a pipe isn't going to do that). But if you are lucky enough to be able to cruise in the big numbers like that for long periods you are going to see the needle come up but as long as it doesn't go very far above 3/4 I reckon you're fine!

OK Herzel, thanks for the fotos and answering...

my questions.

1. Normally the car runs at 190 deg which is midscale. at times it hoovers a bit up and the fan kicks in, I know because the voltmeter drops some.

This sounds like a perfectly NORMAL operation. It can be IMPROVED though. I suggest wiring the A/C fan so it too comes on with the Radiator Fan. This will cool down the temperature in about 1/3 the time. When you operate your A/C, the A/C fan should come on as usual, and the Radiator Fan will cycle on and off as needed. A Diode may need to be placed in the circuit to prevent the Radiator Fan from being on all the time the A/C is. Bob Brown could better tell us how to wire this but its really a simple matter.

at high speed (4k revs in 5th) temp starts climbing. at 5k the temp rose to 3/4 scale which is 225 deg. a At that point I slowed down to 3K and temp dropped slowly.

A GOOD T-Stat will keep the car at the 190 temp and fans cycling with NO temperature rise over 194. Many times I have found T-Stats that do not CLOSE fast enough or CLOSE COMPLETELY. (Yes, I said close...) In this manner, the coolant constantly circulates and never has time to COOL in the radiator. I experienced this problem when the gasket failed around my T-Stat and and coolant continually circulated.

A good test of your T-Stat is to get your car up to operating temperature and then turn on your heater and blower to high.

You will see your temperature drop quite quickly and...

A. A BAD T-Stat or leak-by will hold the temperature lower...
B. A GOOD T-Stat will CLOSE and bring the engine back to its 185 degree operating temperature!

It was a very hot day about 95 degs.

Yes Herzel, there is a Santa Claus and guess what... go ahead, GUESS what the temp is outside my place.!

At the end of an hour's trip water level was up, no loss.

2. I do have A/C

You don't mention if these problems occur with the A/C on or not. I would only ASS-U-ME that if you are having overheating issues... it is NOT. All my experience here has been on non-A/C cars... but I contend that theoretically, the stat and fans should be able to hold the temp down within reason, otherwise what good is it?

3. I have 2 fans but the second one kicks in with the A/C.

I already gave you a suggestion as how to improve this.

I had a heating problem while driving from Texas to your place. She was overheating badly. At times I turned the A/C on just to add that second fan. At a stopover in Vegas I had the radiator off and chemically cleaned. Had no heating problem ever since.
So I tend to think the cooling system is clogged and before taking things apart I thought I''d flush it, hence my questions.

That you can do and at least eliminate that possibility. Tell the shop owner you want the radiator "boiled out chemically" and then pressure tested. Ask him to be truthful and tell you if he saw a problem or not... You are paying anyway, and are NOT going to complain if he found nothing wrong.

As I said in the PM, there are others available in Aluminum and most everyone has had praise for them.

At any rate' here are some pics of the front:






OK... thanks for the fotos... and trust me... I have been doing little things all over my car to keep it cool and at temp for 30+ years. You may get some arguments from the Peanut Gallery, but I stand behind what I am about to share with you from EXPERIENCE and ACCURACY and have been SUCCESSFUL in keeping my car at 190 in traffic on a 103 degree day for 2 hours.

1. Take your FRONT license plate and either mount it up EVEN with the bottom of the bumper, remove it entirely, bend it under the bumper or mount it to the side. That little bit hanging down will force air DOWN and AROUND the radiator. Prove it for yourself with a laser thermometer or a cooking thermometer (in your open reservoir...) or by simply looking at your gauge.

2. Wire the fans as I suggested.

3. Remove the two side scoops and cut off the gridwork so that there are now only Vertical Fins. 30% more air will go through.

4. Remove the RAIN TRAY under the Engine Cover. You will need to fab some bumpers and you can make it re-installable. I have had only ONE occurrence (of course it was super embarrassing...) in some 15 years and that was really due to condensation and dirt. The ICM was not impacted and the Dizzy had condensation inside the cap with a lot of forgotten dirt that caused the car not to start. The temp dropped so fast and it came down so hard it really soaked my engine whilst PARKED. I've never had a problem in normal rain whilst MOVING.

5. Drop the Radiator... flush the engine and pipes and replace the T-Stat and Cap. STANT p/ns are: 45378 for the Stat and 11329 for the Cap. But looky here:



This was the T-Stat I bought at Auto-Zone down the street.

6. Make sure your front spoiler is at the CORRECT angle.. this is very important for correct air flow.

7. When reinstalling the radiator, make SURE it is centered in its mount and not behind it or in front of it. For the same reason as #6.

8. Flush and clean the condenser for maximum air flow.

9. Spin your fans by hand... they should COAST. Spray them down with a little WD40 to insure they are spinning freely

10. Pressure test the system and make sure it maintains pressure for 10 minutes.

That should do it. I don't think you have any head gasket issues from what you said and how it act. HTH...

Well, this is a quite a lecture, Tony.
Firstly - how do you intertwined your comments within my text?

to business, the license plate is less than 1/2" below the bumper. Does that matter?
After considering all said I think I'll go for the radiator cleanup first.
I shall report the results here .
Thanks everybody and have a cool weekend,

Answers...

Well, this is a quite a lecture, Tony.

Well... I just wanted to TRY and cover all bases and explain WHY I suggest you do these things... and in the sequence as well. I try to do the OBVIOUS first, then the EASIEST, then the LEAST EXPENSIVE.

Firstly - how do you intertwined your comments within my text?

Instead of just clicking on "REPLY", click on "QUOTE" instead. That will populate your reply with the other person's post. I try and clean things up a bit, then SPACE out the lines so I can type my responses in between. I also, as you can see, try to make the response OBVIOUS by using Italics, or Bold, or in this case both.

to business, the license plate is less than 1/2" below the bumper. Does that matter?

YES, probably not as much as when my tow-bar adapter took up about the same amount of room left to right, but hanged below the bumper just 2 inches. Traveling at speeds under 60 mph had no effect. Traveling faster than that and it just got hotter and hotter. Dropping below 60 and it cooled down, removing the plate altogether CURED the problem. Even the 1/2 inch hanging below MUST contribute something negatively to the air flow. Test it for yourself... Run the car for a good 15 minutes at speed with the plate on and again over the same course with it off. Others here have tried it with our much smaller plates in NA and can attest to what I am saying.

After considering all said I think I'll go for the radiator cleanup first.

I think that is the best place for YOU to start... as it is actually one of the easiest and the obvious. As I said many times before, dropping the radiator is two 13mm nuts, two clamps, and one wire connector... for a NON-A/C car. I have NOT worked on an A/C car and do not know how the condenser is mounted. Hopefully NOT to the radiator.

But with the radiator out, the coolant is drained... meaning all the hoses (if old) can be easily accessed and replaced, same with the Thermostat, and same with flushing the block and coolant lines. I really suggest you replace that T-Stat as it has been "over-extended" several times and may be over 30 years old! It should not be that expensive as the ones I get here are like 7 bucks and are "Hecho in Israel"!

I shall report the results here.

Good... that's why WE do this... and please be specific with numbers... After all, you do have several Engineering Degrees if I remember correctly.

Thanks everybody and have a cool weekend.

Our forecast is for 102+ for the next 5 days. I believe Bob Brown will be very comfortable in the 70's!