Engine not warming up

[randyo]

I recently bought a boat, and the temperature didnt rise past about 105degrees. My first thought was to check the gauge, it checks out fine-- grounding it makes it pin to the highest temp (about 250). Then I tried the same thing at the temperature sensor and the gauge again pinned to the highest temp, thus I assumed the wire connections were fine also. Next, I thought thermostat stuck open? So I opened the housing and sure enough, it wont close. I replaced that this morning (of course, it was with you guys' help in another thread!) with a new oring and gasket, as well. <br /><br />This afternoon, I took the boat out onto the bay, and though the engine temp is going higher than before (maybe 110 vs 105?), I still dont think the engine is heating up. I bought a temperature gun and pointed it at different parts of the front of the engine. Everywhere registered between 110 and 95 degrees--this was after about 20 minutes of boating on bay water in southern california.<br /><br />1) How long should it take for the engine to warm up?<br />2) What temperature should it warm up to?<br />3) Even though the temp gun and temp gauge agree, should I test my temp sensor? If not, whats the next step?

 

[tommays]

Re: Engine not warming up

its common to not get all the stat parts back in right and run cold<br /><br /><br />

<br /><br /><br />tommays

 

[randyo]

Re: Engine not warming up

Thanks for the diagrams tommays. I re-checked all of the hoses and they appear to be correct. Both hose 7s go to their respective exhaust manifolds. The other two hoses are way different in diameter, so there is no way to easily swap them.<br /><br />I installed the stat just like the one I removed. It made sense and my girlfriend looked at it too and we decided it was on right. If you think I should pull the t-housing again and verify or take pics, I will. Would I need another gasket or the one from this morning would work?<br /><br />Please let me know if there are other suggestions to follow.

 

[randyo]

Re: Engine not warming up

Another thought, maybe the parts shop gave me the wrong thermostat?<br /><br />They gave me the following:<br />Sierra Thermostat Kit<br />18-3677<br />160 Degrees<br />Replaces OMC 3856961<br /><br />My engine is a volvo, but the book they had said this thermostat and it looks and fits just like my old one (though the gasket wasnt totally correct so I bought a gasket at the auto store that matched up better.

 

[Don S]

Re: Engine not warming up

OK, what's the model number of your engine. It should be someting like 4.3GL or GS and then a string of about 5 letteres. Need those letters.

 

[randyo]

Re: Engine not warming up

When I bought the boat, the guy said it was a 4.3GL. The cover for the carb says 4.3GL on it really big. Looking at the engine serial number plate, I believe the "type" says: LB43LTBI<br /><br />the "I believe" is because it is so rediculously difficult to read the thing, I have to dive into the engine compartment to have a look at it, and it hurts like crazy. If this is enough info, great. If you need to know exactly what it says, there are about 10 or so screws I can undo to take the entire sundeck off and gain much better access to the tag.<br /><br />Thanks!

 

[Don S]

Re: Engine not warming up

Don't rip your boat apart looking for numbers, the Volvo number for the LK model that it sounds like you have is the same as the OMC number you listed above. It could be that the new stat got crooked or stuck open. You might pull it apart and have a look.<br />The gasket number is 3852111.

 

[randyo]

Re: Engine not warming up

Thanks guys. I'll take the housing apart again tomorrow and take a look at whats going on inside. I'll probably post a pic or two so others can verify it is installed correctly before I re-install it with a new gasket. Hopefully, thats where the problem lies! Have a great fourth of July!!

 

[randyo]

Re: Engine not warming up

I opened the t-housing today, and the thermostat appears to be correct. Here is a picture of what it looked like when I took the upper housing off:<br /><br />

<br /><br />I then took the o-ring off and pulled the stat, it was closed and nothing seems bent. I put it in water and heated it. At about 155 it started to open. I let it go until 165 and then pulled it out. It started to close up and was fully closed within some-odd seconds.<br /><br />Not sure what to check next, but I am more than willing to try anything anyone here recommends and post my results/pics. I also picked up a Seloc Manual and can reference that for any suggestions anyone has. Thanks!<br /><br />Keep in mind I do have a temperature gun if that might be helpful in diagnosing.

 

[bigdaddyofhouse]

Re: Engine not warming up

Just try another thermostat thats about the only thing it could be. I'll take that back if some one drilled a hole in your head in just the right spot so tha the water from your exhaust could run back into the cooling jacket of your block,that could cause it to run cool all the time.

 

[Lou C]

Re: Engine not warming up

Are you sure it is closing all the way? Esp with a raw water cooled motor in salt water it is possble to get a flake of rust caught between the thermo and the area it seats on, sometimes just running it will clear it out. This just happened to me on my 88 OMC 4.3. I replaced the thermo and housing 2 years ago. Ran exactly at 160 for 2 seasons moored in salt water. Then this season the first few times I used it the temp was normal. One day I noticed it wouldn't get over 120 or so until I ran it for a while, and then it would get up to 160 but would drop down to 120 or so while idling. Then just as suddendly it went back to normal, 160 all the time. My marine mechanic said it was just a flake of rust stopping it from closing all the way. The bay water is probabaly no more than 75 F right? <br />If yours closes and does not have a flake of rust keeping it open, and all the hoses are routed correctly, I'd look again at the temp sender itself, to see if it is reading right at various temps.

 

[randyo]

Re: Engine not warming up

The thermostat itself is working correctly, I tested it in water on the stove. I'll try to re-install everything and try it out in the driveway. Can anyone tell me about how long at idle it should run before it should be reading near 140-150? 10mins? 30mins?<br /><br />Also, in this post for a different engine he mentions putting a "sleeve" on incorrectly? My setup is the upper housing, the stat, the o-ring, the gasket and then lower housing. No sleeve in there anywhere-- is this correct?

 

[randyo]

Re: Engine not warming up

I just found another thread that talks about this plastic sleeve. Should my thermostat housing have something like that? Right now, it definitely doesnt.<br /><br />EDIT: This thread at another forum also depicts a "plastic spacer sleeve". Looking at the blow-up diagram of my cooling system, I dont see any sleeves though...

 

[randyo]

Re: Engine not warming up

Originally posted by tommays:<br /> its common to not get all the stat parts back in right and run cold<br /><br /><br />

<br /><br /><br />tommays

What is part #13 in this picture? Does the thermostat fit into that? If so, that is for sure my problem.

 

[randyo]

Re: Engine not warming up

Turns out volvo engines dont have the plastic sleeve, so I put everything back the way I had originally installed it. Ran it in the driveway, and it got to about 130degrees or so. Ran it in the bay with similar (maybe higher?) temperatures. Then ran it again in the driveway to flush it out and it got to about 155-160degrees. Seems to be working fine, so I'll keep an eye on it. Thanks everyone for your help and diagrams!

 

[thunderroad]

Re: Engine not warming up

#13 appears to be a pipe plug.