Running hot; thermostat? - Honda Prelude Forum

Jonboy10 · 04-03-2010, 07:14 AM

I have a 99 manual that I just got a couple weeks ago. It has 130000 miles and it seems to be running a little hot. The temp gauge will go up as high as it can after about 10 min of driving. And that's not hard driving. But the coolant levels are all fine. So I'm thinking it is the thermostat. I bought a new one and I'm trying to find a website with diagrams on how to change it. If anybody knows of a good site or knows how to do this, let me know.

Thanks!!!

fatmonkee · 04-03-2010, 08:55 AM

Welcome to PO! Let's hope it's the thermostat. You can test it to see if it's accurate. Directions for testing and replacing are in the Helms Manual. Download it here. Here's the index:

Engine
Intake Air System: 11-130
Intake Manifold: 9-2
Header: 9-3
Exhaust: 9-4 (base) 9-5 (sh)
Oil & Filter Change: 8-6
Fuel rail and injectors: 11-124
Replacing Spark plugs: 4-21
Idle Adjustment: 11-115
Valve Adjustment: 6-9
Timing Belt removal: 6-14
Fast Idle thermo valve: 11-141
Thermostat Replacement 10-7
Alternator: 4-29
Troubleshooting Malfunction Indicator Lamp (CEL): 11-36
CEL codes: 11-46
Troubleshooting Driveability Issues with NO CEL: 11:40
PGM-FI System Description: 11-52, 11-53
Fuel filter: 11-127
Radiator Coolant replacement 10-5
How to change the thermostat 10-7

Transmission
Bleeding the clutch hydraulic fluid: 12-6
Replacing Tranny Fluid: 13-3 (manual), 14-122 (auto)
Clutch and flywheel section: 12
Clutch release bearing installation: 12-11
Manual Transmission table of contents: 13-0
Differential Preload adjustment: 13-40
Automatic Transmission table of contents: 14-0
ATTS fluid replacement: 15-67

Brakes
Brakes table of contents: 19-0
Replacing Brake Fluid: 19-7
Parking Brake Adjustment: 19-6

Steering
Reseting the SRS light 24-22
Power Steering: 17-25

Audio
Stereo System Circuit Diagram: 23-152
Audio Unit Removal: 23-153 (Also see section 20-48)
Acoustic Feedback System plug layout: 23-156 (use this for reference when bypassing)

Suspension
Front Suspension: 18-11
Front Suspension removal/installation: 18-20
Rear Suspension: 18-24
Rear Suspension removal/installation: 18-28

Interior
Dashboard Component removal (that piece around the radio): 20-48
Glove box removal: 20-49
Center Console removal: 20-45
Rearview Mirror Removal/installation: 20-15
Troubleshooting your fuel gauge: 11-129
Reseting the SRS light 24-22

Exterior
How To Check Your Windows For Water Leaks: 20-11
Front and rear bumper removal: 20-63 to 20-69

aboone78 · 04-03-2010, 09:59 AM

changing the thermostat is easy.i changed mine last week and it only took about 10 min and thats with me having to take off my CAI and front upper strut bar to get to it.just follow the radiator hose back and take the 2 bolts out of the housing and thats about it.just make sure the new gasket is on properly and that you scrape off any parts of the old one that may still be on there for a good seal.

Jonboy10 · 04-03-2010, 01:29 PM

I changed the thermostat out and double checked all the coolant levels and it's still hot. But the hoses aren't too hot to grab onto after driving. What I did forget to mention is that the gauges are aftermarket. So i'm guessing the heat gauge is really messed up and I'm gonna have to get new gauges. Any suggestions on good working and good looking gauges?

Kronn 98SH · 04-03-2010, 03:59 PM

aftermarket gauges on a lude? show me.

It could be correct and you're still too hot. A clog in the system could cause that.

indylude18 · 04-03-2010, 04:39 PM

Do the radiator fans come on?

Jonboy10 · 04-03-2010, 05:53 PM

Quote:

Originally Posted by indylude18

Do the radiator fans come on?

Yep. The radiator fans both come on. And the gauges are still the same shape but the numbers are different, along with the colors. They are white with blue numbers at night. The needles are original. But there is a switch under the dash that switches the number color from blue to green. But the green switch doesn't work. I just wanna switch them back to OEM if nothing else. They don't look very good.

indylude18 · 04-03-2010, 07:15 PM

I wouldn't rely on gauges with lots of cheesy lighting effects because they are probably cheap crap. The OEM temp gauge is also pretty inaccurate but all you really need it for is to do is tell if the engine is really cold, normal operating temp, or really hot. OEM is more than adequate for that. Unless you happen to have a laser thermometer handy you can't really figure out if you are actually running hot or if your gauge is just reading wrong.

Jonboy10 · 04-03-2010, 11:06 PM

Yeah I want to just get OEM gauges. That would probably be the best way to go. Thanks for all your help.

Kronn 98SH · 04-04-2010, 02:51 PM

Your gauges are OEM. You just have aftermarket faces over them.

Jonboy10 · 04-04-2010, 10:06 PM

So are there aftermarket bulbs behind them? Because there is a switch to change it fro
green to blue. And how hard is it to remove the overlaying faces?

Dog_of_War · 04-04-2010, 10:13 PM

Quote:

Originally Posted by Jonboy10

So are there aftermarket bulbs behind them? Because there is a switch to change it fro
green to blue. And how hard is it to remove the overlaying faces?

They are probably the cheap-o face overlays,.. like these - i682 97-01 HONDA PRELUDE SH MT WHITE FACE GLOW GAUGES : eBay Motors (item 290421705572 end time Apr-07-10 15:04:48 PDT) would take you longer to get your cluster out than to take the overlays off,, 4 screws for the gauge pod cover, 4 more iirc to take the cluster out, unhook the wiring harnesses in the back and un-clip the plastic cover over the bezel, then removing the overlays should be a matter of sliding them off and around the needles, hell if you don't want the overlays, you could carefully just cut them out with some scissors from that point, you'll see when you have it apart, just be careful when you do it and you'll be fine

Kronn 98SH · 04-04-2010, 11:08 PM

Quote:

Originally Posted by Jonboy10

So are there aftermarket bulbs behind them? Because there is a switch to change it fro
green to blue. And how hard is it to remove the overlaying faces?

I already told you to show me. Try listening.

2low · 04-05-2010, 01:52 AM

Make sure that you burp your coolant system. In other words make sure there isn't any air bubbles. Good trick is to fill up your system through the top radiator hose. If the coolant is flowing right and the hose is not as hot as you say than it might just be the gauge as you say.