Hi,

I have a 2000 si that has been overheating. On the way home the other day it blew the heater hose. I replaced that and put a new thermostat in and it still overheats. I left the rad cap off and let it warm up to get the air out but it never did anything. The fan kicked on but it didn't overheat or bubble or even take any coolant. I put the cap on and moved it around the yard then the engine light came on and the temp gauge started to rise.

what am I missing? Thanks

 

What does the cel say? Check for combustion in the coolant? Are you running coolant or water?

 

I have to find some way to read the cel since I can't drive the car anywhere. I also don't know how to check for combustion in the coolant. I'm running honda blue coolnt

 

<p>https://honda-tech.com/honda-civic-d...lists-1901557/</p><p>There ya go, there's your way to read the CEL. &nbsp;Blink codes. &nbsp;To check for combustion gasses in the coolant (what I'm sure tony meant, since actual combustion in the coolant would be so full of wat I'd turn into a white girl who couldn't even), you need to buy/borrow/rent a block tester from your local parts store.</p>

 

Do a block test as NARC suggested. Another way to tell if their is a head-gasket failure is the coolant in the radiator will lower while the coolant level in the overflow tank will increase. If you find yourself adding more coolant lately or in the very near future to the radiator.. then most likely a head-gasket issue. Block-Test will confirm.

If you get extremely lucky it may be just a new OEM radiator cap needed. If so, buy OEM only and not a Stant or other brand..they do not fit correctly.
Also, check for coolant leak at water-pump area.. if it's not leaking it could still be a weak water-pump that hasn't completely failed. Easiest way to check is to leave the cap loose from cold start to operating temp..then with rag remove cap and visually check the coolant in the radiator for circulation. If, water pump is functioning properly there should be a good amount of water flow (in one direction). If not, the pump may be the issue.

When you bled the air from the coolant did you elevate the front end and set the heater (inside car) to max heat?

 

ok this afternoon i'll check the cel then look into the block tester. It had a new head gasket done last year so im crossing my fingers thats not the problem.

 

so the car has been parked since fall and I finally am getting to work on it again. I used a cylinder leakage tester and everything checks out in all cylinders It is no longer throwing any codes. I did as mentioned and let it get up to temp with the cap loose. No coolant moving at all so is it safe to assume I need a water pump? Everything I've read says it would leak which it does not

 

Did you mean block tester^ that detects exhaust gas in the radiator?

Did you bleed exactly like this?
https://honda-tech.com/honda-civic-d.../#post39830585

Under what conditions does the engine overheat?

 

I used a leakage tester the type that puts air into the cylinder. I may try bleeding it again tomorrow the way you suggested ( it was over six months ago that I touched the car so I don't exactly remember what I did). The engine takes a long time to overheat idling but once it has a load on it it overheats quickly.

 

Rent a block tester from AutoZone. The rental is free. You just pay for the testing solution.

Does the radiator fan run when the engine starts to overheat?

Is the engine losing coolant?

 

Does the radiator fan run when the engine starts to overheat?

The fan comes on before the engine overheats and stays on.

Is the engine losing coolant?

The level hasn't moved but it was low when I pulled it in the shop after sitting but there are no leaks unless they are internal or at least I have not seen any and the floor is clean. I took the cover off to see if the water pump was leaking but I can not see any coolant.

 

You should consider pressure testing the cooling system for leaks.

How do you know the thermostat wasn't bad out of the box? Did you buy a Honda one?

Have you ruled out a radiator problem?

 

I actually put in two different thermostats thinking maybe one was bad and no not honda, Stant? I think. I have not ruled out the radiator.